Question

If in two circles, arcs of the same length subtend angles 45° and 60° at Centre, find the ratio of their radii.

(a) 2:3

(b) 2:5

(c) 3:4

(d) 4:3

This question was posed to me in class test.

The doubt is from Trigonometric Functions topic in division Trigonometric Functions of Mathematics – Class 11

Answer 1

The correct answer is (d) 4:3

The explanation: Given θ1=45° and θ2=60°, L1=L2

We know, θ = l/r

r1 θ1 = r2 θ2

r1/r2=60/45=4/3.

So, radii are in ratio 4:3.