Mensurationhard · Past Paper
If the area of a circle is doubled, its radius increases by a factor of:
A2
Bsqrt(2)
C4
D1.44
✓ Correct Answer: B — sqrt(2)
A2 = 2*A1 => pi*r2^2 = 2*pi*r1^2 => r2 = sqrt(2)*r1.
Share this question
More from Mensuration
- What is the area of a sheet needed to make an open cylinder (no top) with radius 'r' and height 'h'?
- Find the area of a quadrilateral ABCD where AB=7, BC=24, CD=20, DA=15 and angle ABC=90.
- A hemispherical tank full of water is emptied by a pipe at the rate of 25/7 liters per second. How much time will it take to empty half the tank, if it is 3 m in diameter?
- If the height of a cylinder is doubled and the radius is halved, the new curved surface area will be:
- Calculate the surface area of a sphere if its radius is 0.7 cm.