Question

(5) Two arcs of the same lengths subtend
angles of 60° and 75° at the centres of
two circles. What is the ratio of radii of
two circles ?​

Answer 1

Answer:

5:4

explanation:60°=π/3

75=5π/12

l=r1×π/3

l=r2×5π/12

l=l(given)

r1+π/3=r2+5π/12

r1/r2=π/3÷5π/12=(5/12)×3

r1/r2=5/4

r1:r2=5:4

Answer 2

Ans   We know that length of an arc is given by,

S = R*X , where X = angle subtended by the arc at center in degrees.

Using this,

S = A*60

S = B*75 ,

ratio of radii = A/B = 75/60 = 5/4