A tree of height 6 m casts a shadow of 4m and at the same time a tower casts a shadow of 28 m find the height of the tower

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asked Jan 27, 2018 in Mathematics by Elsa (30 points)

A tree of height 6 m casts a shadow of 4m and at the same time a tower casts a shadow of 28 m. find the height of the tower.

Heights and distances,Class 10

1 Answer

+1 vote
answered Jan 28, 2018 by Prabhat shukla (704 points) 9

Length of the vertical pole = 6m (Given)

Shadow of the tree = 4 m (Given)

Let Height of tower = h m

Length of shadow of the tower = 28 m (Given)

In ΔABC and ΔDEF,

image

∠C = ∠E (angular elevation of sum)

∠B = ∠F = 90°

∴ ΔABC ~ ΔDEF (By AA similarity criterion)

∴ AB/DF = BC/EF (If two triangles are similar corresponding sides are proportional)

∴ 6/h = 4/28

⇒ h = 6×28/4

⇒ h = 6 × 7

⇒ = 42 m

Hence, the height of the tower is 42 m.

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