Arithmeticmedium · Past Paper
If the radius of a circle is increased by 50%, what is the percentage increase in its area?
A50%
B100%
C125%
D150%
✓ Correct Answer: C — 125%
Area is proportional to r^2. New area factor = (1.5)^2 = 2.25. Increase = 2.25 - 1 = 1.25 = 125%.
Share this question
More from Arithmetic
- The ratio of three numbers is 1/2 : 2/3 : 3/4. If the difference between the largest and smallest is 36, find the numbers.
- If A's income is 25% more than B's income, then B's income is how much percent less than A's?
- Find the value of x such that 12, 18, x are in continued proportion.
- A number x is 20% less than y and y is 10% more than 100. What is x?
- A number is increased by 25%. By what percent should it be decreased to get back original number?