Area of triangle w/ explanation

Find the area of the triangle ABC.

• 8 cm²

• 20 cm²

• 28 cm²

• 40 cm²

Answer explanation

Area of triangle ABC

= ½ b x h

= ½ CB x AB

= ½ (4 cm) x (10 cm)

= 20 cm²

What is the area of the triangle JLK?

• 10 m²

• 14 m²

• 70 m²

• 140 m²

Answer explanation

Area of triangle JLK

= ½ b x h

= ½ LK x JM

= ½ (14 m) x(10 m)

= 70 m²

Find the area of the triangle WXY.

• 20 cm²

• 27cm²

• 28 cm²

• 56 cm²

Answer explanation

Base YX of triangle WYX is 8 cm. Perpendicular height to base YX of triangle WYX is 7 cm.

Area of triangle WXY

= ½ b x h

= ½ (8 cm) x (7 cm)

= 28 cm²

Given that the area of the triangle ABC is 48 cm², find the base BC of the triangle ABC that is perpendicular to its height AD of 6 cm.

Answer explanation

Area of triangle ABC = 48 cm²

½ base x its perpendicular height = 48 cm²

½ base BC  x AD    = 48 cm²

½ base BC  x 6 cm = 48 cm² 

½ base BC = 8 cm

base BC

= 2 x 8 cm

= 16 cm

In the figure below, QRS is a straight line.

Find the area of triangle PQR.

Answer explanation

Area of triangle PQR

= ½ b x h

= ½ RQ x SP

= ½ (10 cm) x (14 cm)

= 70 cm²

Look at the figure below.

Given that PS = 9 cm, SQ = 28 cm, PR = 14 cm and SR = 12 cm,

find the area of triangle PRQ.

Answer explanation

Ans: RQ = 28 – 12               

= 16 cm       

Area of triangle PRQ

= ½ b x h                         

= ½ RQ x PS                      

= ½ (16 cm) X (9cm)

= 72cm²   

QRSV is a rectangle.

Find the area of the shaded triangle QST.

Answer explanation

Area of triangle = ½ b x h

= ½ TS x QV

= ½ (2 cm) x(4 cm)

= 4 cm²