Question

If the circumference of a circle exceeds it
diameter by 30, then find the radius of the
circle.​

Answer 1

GIVEN:

• circumference of circle exceeds diameter by 30.

TO FIND:

• Radius of circle

SOLUTION:

According to the question:-

$\large \sf \underline{ \underline{2πr=2r+30}}$

$\sf : \implies \: \: 2πr-r=30$

$\sf : \implies \: \: 2r(π-1)=30$

$: \implies \: \: \sf2r( \frac{22}{7} - 1) = 30$

$: \implies \: \: \sf2r( \frac{22 - 7}{7} ) = 30$

$: \implies \: \: \sf2r \times \frac{15}{7} = 30$

$: \implies \: \: \sf r = \frac{30 \times 7}{15 \times 2}$

$\large \boxed{ \sf r = 7cm}$

So radius=7cm

RELATED FORMULAE:

• Area of circle=πr²
• Circumference of circle=2πr