Paper 1 · Mathematical Reasoning and Aptitude
The radius of a circle increases by 20%. By what percentage does its area increase?
A33%
B44% ✓ Correct
C55%
DNone of the above
Correct answer: (B) 44% — The area increases by 44%, so that is the answer.
Explanation
★The area increases by 44%, so that is the answer.
★The area of a circle is proportional to the square of the radius.
★If the radius becomes 1.2 times, the area becomes 1.2 squared times.
★1.2 squared is 1.44.
★So the area becomes 1.44 times the original, a rise of 0.44.
★So the area increases by 44%.
Want more like this? Create a free account to practise a full test, track your progress, and get spaced-repetition review.
Shared by Mcqkart · via Mcqkart.in