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Question
Triangles ABC and DEF are similar.
If area (ΔABC) = 9 cm2, area (ΔDEF) = 64 cm2 and DE = 5.1 cm, find AB.
Solution
We have
area (Δ ABC) = 9 cm2
area (Δ DEF) = 64 cm2
and DE = 5.1 cm
Since, `"area (Δ ABC)"/"area (Δ DEF)" = "AB"^2/"DE"^2`
⇒ `(9)/(64) = "AB"^2/"DE"^2`
⇒ `"AB"/"DE" = (3)/(8)`
⇒ `"AB"/(5.1) = (3)/(8)`
⇒ AB = `(3)/(8) xx 5.1 = (15.3)/(8)`
⇒ AB = 1.9125 cm.
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