2. In Δ ABC, DEIBC., If DE3 BC and area of Δ ABC-81 cm2 , find the a

1.	2. In Δ ABC, DEIBC., If DE3 BC and area of Δ ABC-81 cm2 , find the area of Δ ADE.
Answer» In triangle ADE and triangle ABC angle A = angle A ( common ) angle ADE = angle ABC ( corresponding angles, DE is parallel to BC) therefore, triangle ADE is similar to triangle ABC ( by AA corollary of AAA) area of triangleADE / area of triangle ABC = (DE)^2 / (BC)^2 area of triangle ADE / 81 = (2/3 BC)^2 / (BC)^2 area of trangle ADE / 81 = 4BC^2 / 9 / BC^2 area of triangle ADE = 4 / 9 * 81 area of triangle ADE= 36 cm^2 it's not answer

2. In Δ ABC, DEIBC., If DE3 BC and area of Δ ABC-81 cm2 , find the area of Δ ADE.

Answer»

In triangle ADE and triangle ABC

angle A = angle A ( common )

angle ADE = angle ABC ( corresponding angles, DE is parallel to BC)

therefore, triangle ADE is similar to triangle ABC ( by AA corollary of AAA)

area of triangleADE / area of triangle ABC = (DE)^2 / (BC)^2

area of triangle ADE / 81 = (2/3 BC)^2 / (BC)^2

area of trangle ADE / 81 = 4BC^2 / 9 / BC^2

area of triangle ADE = 4 / 9 * 81

area of triangle ADE= 36 cm^2

it's not answer