Question

Q19. If A ABC~A DEF and area CD ABC) = 81cm² ,area D E F )=64
cm2? then AB: DE=
​

Answer 1

Step-by-step explanation:

(i)  We know that the ratio of area of two similar triangles is equal to the ratio of squares of their corresponding sides.

∴  area(△DEF)area(△ABC)=(EFBC)2

⇒ 2516=(EF2.3)2

⇒  54=EF2.3

⇒  EF=42.3×5

∴  EF=2.875cm

(ii) We know that the ratio of area of two similar triangles is equal to the ratio of squares of their corresponding sides.

∴  area(△DEF)area(△ABC)=(DEAB)2

⇒ 649=(DEAB)2

⇒  83=5.1AB

∴  AB=1.91cm

(iii) We know that the ratio of area of two similar triangles is equal to the ratio of squares of their corresponding sides.

∴