Question

the difference between circumference and diameter of a circle is 21.4cm find the radius
​

Answer 1

Given,

πr² - 2πr = 21.4

π (r² - 2r) = 21.4

r² - 2r = 21.4 × 7/ 22

r² - 2r = 6.80

r² - 2r - 6.8 = 0 (Quad. Eqn)

r = 3.792, -1.79

Since the value of radius cannot be Negative, therefore r = 3.79.

Radius = 3.79 cm

Answer 2

Answer:

749/290

Step-by-step explanation:

A.T.Q:-

πd+d=21.4

d(22/7+1)=214/10

d(29/7)=214/10

d=214/10×7/29

d=1498/290

r=d/2

so,r=1498/2×290

r=749/290