Thrice the length of the diameter of a circle is 10 cm less than its circumference. What is the radius of the circle? [Use π = $\frac{22}{7}$]
Answer & explanation
Correct answer: option 4
We know that,
Circumference of a circle =2πr
Given that,
3d = circumference - 10 cm
= as diameter = 2 radius
= 3 × 2r = 2πr -10
= 6r = 2× \(\frac{22}{7}\)× r - 10
= \(\frac{44}{7}\)r - 6r = 10
= \(\frac{2r}{7}\)= 10
r = 35cm