Scroll:Measurement >> Area of Triangle >> ps (1314)


Written Instructions:

For each Multiple Choice Question (MCQ), four options are given. One of them is the correct answer. Make your choice (1,2,3 or 4). Write your answers in the brackets provided..

For each Short Answer Question(SAQ) and Long Answer Question(LAQ), write your answers in the blanks provided.

Leave your answers in the simplest form or correct to two decimal places.



 

1)  

ABCD is a square of area 144cm2 . E and F are midpoints of AD and AB respectively. 

Find the area of the shaded triangle. 

cm2


Answer:_______________




2)  

ABCD is a rectangle of area 132cm2 . B and F are midpoints of AC and AE respectively. 

Find the area of the shaded triangle. 

cm2


Answer:_______________




3)  

ABCD is a square of area 64cm2 . E and F are midpoints of AD and AB respectively. 

Find the area of the shaded triangle. 

cm2


Answer:_______________




4)  

ABCD is a rectangle of area 160cm2 . B and F are midpoints of AC and AE respectively. 

Find the area of the shaded triangle. 

cm2


Answer:_______________




5)  

ABCD is a square of area 36cm2 . E and F are midpoints of AD and AB respectively. 

Find the area of the shaded triangle. 

cm2


Answer:_______________




6)  

ABCD is a rectangle of area 260cm2 . B and F are midpoints of AC and AE respectively. 

Find the area of the shaded triangle. 

cm2


Answer:_______________




7)  

ABCD is a square of area 100cm2 . E and F are midpoints of AD and AB respectively. 

Find the area of the shaded triangle. 

cm2


Answer:_______________




8)  

ABCD is a rectangle of area 180cm2 . B and F are midpoints of AC and AE respectively. 

Find the area of the shaded triangle. 

cm2


Answer:_______________




9)  

ABCD is a square of area 16cm2 . E and F are midpoints of AD and AB respectively. 

Find the area of the shaded triangle. 

cm2


Answer:_______________




10)  

ABCD is a rectangle of area 96cm2 . B and F are midpoints of AC and AE respectively. 

Find the area of the shaded triangle. 

cm2


Answer:_______________




 

1)  

ABCD is a square of area 144cm2 . E and F are midpoints of AD and AB respectively. 

Find the area of the shaded triangle. 

Answer: 54 cm2


SOLUTION 1 :

 

 

 

 

 

 

 

6 cm

                                       12 cm

Step 1: Area of square ABCD → 12 cm x 12 cm = 144 cm2

Step 2: Length of AF → 12 cm ÷ 2 = 6 cm

Step 3: Area of triangle AFE →   12 x 6 cm x 6 cm = 18 cm2

Step 4: Area of triangle CDE → 12 x 6 cm x 12 cm = 36 cm2

Step 5: Area of triangle CBF → 12 x 6 cm x 12 cm = 36 cm2

Step 6: 18 cm2 + 36 cm2 + 36 cm2 = 90cm2

Step 7: 144 cm2 - 90 cm2 = 54 cm2



2)  

ABCD is a rectangle of area 132cm2 . B and F are midpoints of AC and AE respectively. 

Find the area of the shaded triangle. 

Answer: 49.5 cm2


SOLUTION 1 :

 

 

 

 

 3 cm

                                                 22 cm

Step 1: Area of rectangle ACDE → 22 cm x 6 cm = 132 cm2

Step 2: Length of AB → 22 cm ÷ 2 = 11 cm

Step 3: Lenght of AF → 6 cm ÷ 2 = 3 cm

Step 4: Area of triangle ABF →   12 x 11 cm x 3 cm = 16.5 cm2

Step 5: Area of triangle CDB → 12 x 11 cm x 6 cm = 33 cm2

Step 6: Area of triangle DEF → 12 x 22 cm x 3 cm = 33 cm2

Step 7: 16.5 cm2 + 33 cm2 + 33 cm2 = 82.5cm2

Step 8: Area of shaded triangle → 132 cm2 - 82.5 cm2 = 49.5 cm2



3)  

ABCD is a square of area 64cm2 . E and F are midpoints of AD and AB respectively. 

Find the area of the shaded triangle. 

Answer: 24 cm2


SOLUTION 1 :

 

 

 

 

 

 

 

4 cm

                                       8 cm

Step 1: Area of square ABCD → 8 cm x 8 cm = 64 cm2

Step 2: Length of AF → 8 cm ÷ 2 = 4 cm

Step 3: Area of triangle AFE →   12 x 4 cm x 4 cm = 8 cm2

Step 4: Area of triangle CDE → 12 x 4 cm x 8 cm = 16 cm2

Step 5: Area of triangle CBF → 12 x 4 cm x 8 cm = 16 cm2

Step 6: 8 cm2 + 16 cm2 + 16 cm2 = 40cm2

Step 7: 64 cm2 - 40 cm2 = 24 cm2



4)  

ABCD is a rectangle of area 160cm2 . B and F are midpoints of AC and AE respectively. 

Find the area of the shaded triangle. 

Answer: 60 cm2


SOLUTION 1 :

 

 

 

 

 4 cm

                                                 20 cm

Step 1: Area of rectangle ACDE → 20 cm x 8 cm = 160 cm2

Step 2: Length of AB → 20 cm ÷ 2 = 10 cm

Step 3: Lenght of AF → 8 cm ÷ 2 = 4 cm

Step 4: Area of triangle ABF →   12 x 10 cm x 4 cm = 20 cm2

Step 5: Area of triangle CDB → 12 x 10 cm x 8 cm = 40 cm2

Step 6: Area of triangle DEF → 12 x 20 cm x 4 cm = 40 cm2

Step 7: 20 cm2 + 40 cm2 + 40 cm2 = 100cm2

Step 8: Area of shaded triangle → 160 cm2 - 100 cm2 = 60 cm2



5)  

ABCD is a square of area 36cm2 . E and F are midpoints of AD and AB respectively. 

Find the area of the shaded triangle. 

Answer: 13.5 cm2


SOLUTION 1 :

 

 

 

 

 

 

 

3 cm

                                       6 cm

Step 1: Area of square ABCD → 6 cm x 6 cm = 36 cm2

Step 2: Length of AF → 6 cm ÷ 2 = 3 cm

Step 3: Area of triangle AFE →   12 x 3 cm x 3 cm = 4.5 cm2

Step 4: Area of triangle CDE → 12 x 3 cm x 6 cm = 9 cm2

Step 5: Area of triangle CBF → 12 x 3 cm x 6 cm = 9 cm2

Step 6: 4.5 cm2 + 9 cm2 + 9 cm2 = 22.5cm2

Step 7: 36 cm2 - 22.5 cm2 = 13.5 cm2



6)  

ABCD is a rectangle of area 260cm2 . B and F are midpoints of AC and AE respectively. 

Find the area of the shaded triangle. 

Answer: 97.5 cm2


SOLUTION 1 :

 

 

 

 

 5 cm

                                                 26 cm

Step 1: Area of rectangle ACDE → 26 cm x 10 cm = 260 cm2

Step 2: Length of AB → 26 cm ÷ 2 = 13 cm

Step 3: Lenght of AF → 10 cm ÷ 2 = 5 cm

Step 4: Area of triangle ABF →   12 x 13 cm x 5 cm = 32.5 cm2

Step 5: Area of triangle CDB → 12 x 13 cm x 10 cm = 65 cm2

Step 6: Area of triangle DEF → 12 x 26 cm x 5 cm = 65 cm2

Step 7: 32.5 cm2 + 65 cm2 + 65 cm2 = 162.5cm2

Step 8: Area of shaded triangle → 260 cm2 - 162.5 cm2 = 97.5 cm2



7)  

ABCD is a square of area 100cm2 . E and F are midpoints of AD and AB respectively. 

Find the area of the shaded triangle. 

Answer: 37.5 cm2


SOLUTION 1 :

 

 

 

 

 

 

 

5 cm

                                       10 cm

Step 1: Area of square ABCD → 10 cm x 10 cm = 100 cm2

Step 2: Length of AF → 10 cm ÷ 2 = 5 cm

Step 3: Area of triangle AFE →   12 x 5 cm x 5 cm = 12.5 cm2

Step 4: Area of triangle CDE → 12 x 5 cm x 10 cm = 25 cm2

Step 5: Area of triangle CBF → 12 x 5 cm x 10 cm = 25 cm2

Step 6: 12.5 cm2 + 25 cm2 + 25 cm2 = 62.5cm2

Step 7: 100 cm2 - 62.5 cm2 = 37.5 cm2



8)  

ABCD is a rectangle of area 180cm2 . B and F are midpoints of AC and AE respectively. 

Find the area of the shaded triangle. 

Answer: 67.5 cm2


SOLUTION 1 :

 

 

 

 

 3 cm

                                                 30 cm

Step 1: Area of rectangle ACDE → 30 cm x 6 cm = 180 cm2

Step 2: Length of AB → 30 cm ÷ 2 = 15 cm

Step 3: Lenght of AF → 6 cm ÷ 2 = 3 cm

Step 4: Area of triangle ABF →   12 x 15 cm x 3 cm = 22.5 cm2

Step 5: Area of triangle CDB → 12 x 15 cm x 6 cm = 45 cm2

Step 6: Area of triangle DEF → 12 x 30 cm x 3 cm = 45 cm2

Step 7: 22.5 cm2 + 45 cm2 + 45 cm2 = 112.5cm2

Step 8: Area of shaded triangle → 180 cm2 - 112.5 cm2 = 67.5 cm2



9)  

ABCD is a square of area 16cm2 . E and F are midpoints of AD and AB respectively. 

Find the area of the shaded triangle. 

Answer: 6 cm2


SOLUTION 1 :

 

 

 

 

 

 

 

2 cm

                                       4 cm

Step 1: Area of square ABCD → 4 cm x 4 cm = 16 cm2

Step 2: Length of AF → 4 cm ÷ 2 = 2 cm

Step 3: Area of triangle AFE →   12 x 2 cm x 2 cm = 2 cm2

Step 4: Area of triangle CDE → 12 x 2 cm x 4 cm = 4 cm2

Step 5: Area of triangle CBF → 12 x 2 cm x 4 cm = 4 cm2

Step 6: 2 cm2 + 4 cm2 + 4 cm2 = 10cm2

Step 7: 16 cm2 - 10 cm2 = 6 cm2



10)  

ABCD is a rectangle of area 96cm2 . B and F are midpoints of AC and AE respectively. 

Find the area of the shaded triangle. 

Answer: 36 cm2


SOLUTION 1 :

 

 

 

 

 2 cm

                                                 24 cm

Step 1: Area of rectangle ACDE → 24 cm x 4 cm = 96 cm2

Step 2: Length of AB → 24 cm ÷ 2 = 12 cm

Step 3: Lenght of AF → 4 cm ÷ 2 = 2 cm

Step 4: Area of triangle ABF →   12 x 12 cm x 2 cm = 12 cm2

Step 5: Area of triangle CDB → 12 x 12 cm x 4 cm = 24 cm2

Step 6: Area of triangle DEF → 12 x 24 cm x 2 cm = 24 cm2

Step 7: 12 cm2 + 24 cm2 + 24 cm2 = 60cm2

Step 8: Area of shaded triangle → 96 cm2 - 60 cm2 = 36 cm2