RRB Group-D Model Paper 14 with answers for online practice

Question : 76 of 100

Marks: +1, -0

A right-angled triangle ABC is right-angled at B, and tan A = 4/3. If AC = 25 cm, the length of BC is:

Solution:

Given, tan A = 4/3 = BC/AB
Let BC = 4x and AB = 3x
By Pythagoras theorem,

AC^2 = AB^2 + BC^2

⇒

25^2 = (3x)^2 + (4x)^2

⇒

625 = 9x^2 + 16x^2

⇒

625 = 25x^2

⇒

x^2

= 25
⇒ x = 5∴ length of BC = 4x = 4 × 5 = 20 cm

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