CameraIcon
CameraIcon
SearchIcon
MyQuestionIcon


Question

On decreasing the radius of a circle by 30 %, its area is decreased by

(a) 30 %                  (b) 60 %               (c) 45%                  (d) none of these
 


Solution

Let the radius of the circle be r cm

So, area of the circle = πr2

Now, radius decrease by 30%

So, the new radius = 0.7r 

Area of the circle with new radius = π(0.7r)2 = 0.49r2π

Change in the area =  πr2 - 0.49r2×π 

= 0.51r2 ×π

% change in area = 0.51×r2×πr2×π × 100% 
= 51%
Hence, the correct option is (d).


Mathematics
Secondary School Mathematics X
Standard X

Suggest Corrections
thumbs-up
 
17


similar_icon
Similar questions
View More


similar_icon
Same exercise questions
View More


similar_icon
People also searched for
View More



footer-image