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

Find the area of the shaded triangle. 

cm2


Answer:_______________




2)  

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:_______________




3)  

ABCD is a rectangle of area 120cm2 . B and F are midpoints of AC and AE respectively. 

Find the area of the shaded triangle. 

cm2


Answer:_______________




4)  

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:_______________




5)  

ABCD is a rectangle of area 156cm2 . B and F are midpoints of AC and AE respectively. 

Find the area of the shaded triangle. 

cm2


Answer:_______________




6)  

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:_______________




7)  

ABCD is a rectangle of area 88cm2 . B and F are midpoints of AC and AE respectively. 

Find the area of the shaded triangle. 

cm2


Answer:_______________




8)  

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:_______________




9)  

ABCD is a rectangle of area 176cm2 . B and F are midpoints of AC and AE respectively. 

Find the area of the shaded triangle. 

cm2


Answer:_______________




10)  

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:_______________




 

1)  

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



2)  

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



3)  

ABCD is a rectangle of area 120cm2 . B and F are midpoints of AC and AE respectively. 

Find the area of the shaded triangle. 

Answer: 45 cm2


SOLUTION 1 :

 

 

 

 

 3 cm

                                                 20 cm

Step 1: Area of rectangle ACDE → 20 cm x 6 cm = 120 cm2

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

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

Step 4: Area of triangle ABF →   12 x 10 cm x 3 cm = 15 cm2

Step 5: Area of triangle CDB → 12 x 10 cm x 6 cm = 30 cm2

Step 6: Area of triangle DEF → 12 x 20 cm x 3 cm = 30 cm2

Step 7: 15 cm2 + 30 cm2 + 30 cm2 = 75cm2

Step 8: Area of shaded triangle → 120 cm2 - 75 cm2 = 45 cm2



4)  

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



5)  

ABCD is a rectangle of area 156cm2 . B and F are midpoints of AC and AE respectively. 

Find the area of the shaded triangle. 

Answer: 58.5 cm2


SOLUTION 1 :

 

 

 

 

 3 cm

                                                 26 cm

Step 1: Area of rectangle ACDE → 26 cm x 6 cm = 156 cm2

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

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

Step 4: Area of triangle ABF →   12 x 13 cm x 3 cm = 19.5 cm2

Step 5: Area of triangle CDB → 12 x 13 cm x 6 cm = 39 cm2

Step 6: Area of triangle DEF → 12 x 26 cm x 3 cm = 39 cm2

Step 7: 19.5 cm2 + 39 cm2 + 39 cm2 = 97.5cm2

Step 8: Area of shaded triangle → 156 cm2 - 97.5 cm2 = 58.5 cm2



6)  

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



7)  

ABCD is a rectangle of area 88cm2 . B and F are midpoints of AC and AE respectively. 

Find the area of the shaded triangle. 

Answer: 33 cm2


SOLUTION 1 :

 

 

 

 

 2 cm

                                                 22 cm

Step 1: Area of rectangle ACDE → 22 cm x 4 cm = 88 cm2

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

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

Step 4: Area of triangle ABF →   12 x 11 cm x 2 cm = 11 cm2

Step 5: Area of triangle CDB → 12 x 11 cm x 4 cm = 22 cm2

Step 6: Area of triangle DEF → 12 x 22 cm x 2 cm = 22 cm2

Step 7: 11 cm2 + 22 cm2 + 22 cm2 = 55cm2

Step 8: Area of shaded triangle → 88 cm2 - 55 cm2 = 33 cm2



8)  

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



9)  

ABCD is a rectangle of area 176cm2 . B and F are midpoints of AC and AE respectively. 

Find the area of the shaded triangle. 

Answer: 66 cm2


SOLUTION 1 :

 

 

 

 

 4 cm

                                                 22 cm

Step 1: Area of rectangle ACDE → 22 cm x 8 cm = 176 cm2

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

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

Step 4: Area of triangle ABF →   12 x 11 cm x 4 cm = 22 cm2

Step 5: Area of triangle CDB → 12 x 11 cm x 8 cm = 44 cm2

Step 6: Area of triangle DEF → 12 x 22 cm x 4 cm = 44 cm2

Step 7: 22 cm2 + 44 cm2 + 44 cm2 = 110cm2

Step 8: Area of shaded triangle → 176 cm2 - 110 cm2 = 66 cm2



10)  

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