Question

If the radius of a circle is decreased by 50%, its area is decreased by:
A. 75%. B. 50%
C. 85%. D. 65%

Answer 1

Hey dear ☺️

Here your answer
⬇️⬇️⬇️⬇️⬇️⬇️⬇️⬇️⬇️⬇️⬇️⬇️⬇️⬇️⬇️⬇️

➡️Suppose

Old radius of circle is r

And new radius is R

Old area of circle = πr²

&

New area of circle = πR²

But we have given that new radius have decrease 50% to new radius

so we can write that R = r/2

so....

new area of circle = π (r/2)²

= πr²/4

= 0.25 πr²

=> πr²-0.25 πr²= 0.75 πr²

your answer= 0.75×100=75℅