Examples with solutions for Area of a Circle for ninth grade: Impact of a radius change on the area of a circle

Exercise #1

Below are four circles together with their radius measurements.

12342r=14r=62r=10r=2

Which circle has the largest area?

Video Solution

Answer

Circle 1

Exercise #2

Below are four squares together with the measurements of their radii.

12342r=14r=62r=10r=2

Which circle has the smallest area?

Video Solution

Answer

Circle 4

Exercise #3

There are two circles.

One circle has a radius of 4 cm, while the other circle has a radius of 10 cm.

How many times greater is the area of the second circle than the area of the first circle?

Video Solution

Answer

614 6\frac{1}{4}

Exercise #4

There are two circles.

The length of the radius of circle 1 is 6 cm.

The length of the diameter of circle 2 is 12 cm.

How many times greater is the area of circle 2 than the area of circle 1?

Video Solution

Answer

They are equal.

Exercise #5

There are two circles.

The length of the diameter of circle 1 is 4 cm.

The length of the diameter of circle 2 is 10 cm.

How many times larger is the area of circle 2 than the area of circle 1?

Video Solution

Answer

614 6\frac{1}{4}