Question

Two circles have the same radius. Complete the description for whether the combined area of the two circles is the same as the area of a circle with twice the radius. The combined area of two circles with the same radius is ___πr2. The area of a circle with twice the radius is ___πr2. The combined area of two circles is as the area of a circle with twice the radius.

Answer 1

2 ; 4

'is not some as'

Explanation:

Let r be the radius of one circle:

Area of 2 circles = 2(pi×r²) = 2pi×r²

Double the radius: 2r

Area = pi × (2r)² = pi × 4r² = 4pi×r²

Answer 2

see below

Explanation:

A = pi r^2

If they have the same radius they have the same area

A two circles = pi r^2 +pi r^2

= 2 pi r^2

If we double the radius

A = pi (2r)^2

= pi 4r^2

The combined area of two circles is 1/2 the area as the area of a circle with twice the radius.