Question : If the radius of a circle is increased by 10%, what will be the percentage increase in the area of the circle?
Option 1: 19
Option 2: 20
Option 3: 21
Option 4: 23
Correct Answer: 21
Solution : Let the radius of the original circle = $r$ So, the area of the original circle = $\pi r^2$ Radius of circle after 10% increase = $r+\frac{10r}{100} =1.1r$ Area of new circle = $\pi \times 1.1^2 = 1.21r^2$ Percentage increase in area = $\frac{1.21\pi r^2- \pi r^2}{\pi ^2}\times 100$ = 21% Hence, the correct answer is 21.
Application | Eligibility | Selection Process | Result | Cutoff | Admit Card | Preparation Tips
Question : If the radius of a circle is increased by 50%, then what will be the percentage increase in the area of the circle?
Option 1: 225
Option 2: 125
Option 3: 150
Option 4: 175
Question : If the height of the cylinder is increased by 35% and the radius is increased by 10%, what will be the percentage increase in the curved surface area of a cylinder?
Option 1: 46.5
Option 2: 45
Option 3: 48.5
Option 4: 49.7
Question : The radius of circle A is twice that of circle B and the radius of circle B is twice that of circle C. Their area will be in the ratio:
Option 1: 16 : 4 : 1
Option 2: 4 : 2 : 1
Option 3: 1 : 2 : 4
Option 4: 1 : 4 : 16
Question : Which of the following statements is not correct?
Option 1: For a given radius and height, a right circular cone has a lesser volume than a right circular cylinder.
Option 2: If the side of a cube is increased by 10%, the volume will increase by 33.1%.
Option 3: If the radius of a sphere is increased by 20%, the surface area will increase by 40%.
Option 4: Cutting a sphere into 2 parts does not change the total volume.
Question : If the radius of a circle is increased by 16%, its area increases by
Option 1: 34.56%
Option 2: 32%
Option 3: 16%
Option 4: 17.28%
Regular exam updates, QnA, Predictors, College Applications & E-books now on your Mobile