Question

Work out the area of the trapezium ABDE. A В. 7.5 cm 2.5 cm С 5 cm E

Answer 1

Answer:

Area = 50 cm²

Step-by-step explanation:

Area of a trapezium ABDE = ½(a + b)h

where,

a = BD = 2.5 cm

b = AE = 7.5 cm

h = DE = ?

We need to find DE ti be able to calculate the area.

DE = CE - CD

DE = CE - 5

Since ∆ACE is similar to ∆BCD, therefore:

AE/BD = CE/CD

Plug in the values

7.5/2.5 = CE/5

Cross multiply

CE*2.5 = 7.5*5

CE*2.5 = 37.5

Divide both side any 2.5

CE = 37.5/2.5

CE = 15

Thus, DE = CE - 5 = 15 - 5

DE = 10

✅Area of trapezium = ½(BD + AE)DE

= ½(2.5 + 7.5)*10

= ½(10)10

= 50 cm²