If the radius of a circle is increased by 25%, its area increases by:
- A50 percent
- B25 percent
- C28.125 percent
- D56.25 percent
Solution & Step-by-step Explanation
The area of a circle is proportional to the square of its radius (A∝r
2
).
When a quantity increases by x%, the effective percentage increase in its square is given by the successive percentage formula:
Percentage Increase=x+x+
100
x×x
Given x=25%:
Percentage Increase=25+25+
100
25×25
Percentage Increase=50+
100
625
=50+6.25=56.25%
2
).
When a quantity increases by x%, the effective percentage increase in its square is given by the successive percentage formula:
Percentage Increase=x+x+
100
x×x
Given x=25%:
Percentage Increase=25+25+
100
25×25
Percentage Increase=50+
100
625
=50+6.25=56.25%