Question

(Pls do solution or take picture)In the figure, ACEF is a rectangle and BC = CD DE The area of rectangle ACEF is 80 cm. Find the area of the triangle BDF.​

Answer 1

28 cm²

Explanation:

The area of Δ BDF is the area of the rectangle subtract the area of the 3 white triangles.

Since the area of the rectangle = 80 cm² and

area = length × breadth, then

breadth = 80 ÷ 10 = 8 cm

Thus CE = EF = 8 cm and CD = DE = BC = 4 cm

Area of Δ DEF = 0.5 × 10 × 4 = 20 cm²

Area of Δ ABF = 0.5 × 8 × (10 - 4) = 0.5 × 8 × 6 = 24 cm²

Area of Δ BCD = 0.5 × 4 × 4 = 8 cm²

Thus

area of Δ BDF = 80 - (20 + 24 + 8) = 80 - 52 = 28 cm²