The perimeter of two circles are in the ratio 2 : 3. Find the area of ...
Understanding the Problem
We are given that the perimeter of two circles is in the ratio 2:3. We need to find the ratio of their areas.
Perimeter of a Circle
The perimeter of a circle is the distance around its outer edge. It is also known as the circumference of the circle. The formula to calculate the perimeter of a circle is given by:
P = 2πrWhere P is the perimeter, and r is the radius of the circle.
Finding the Ratio of Perimeters
Let's assume the perimeters of the two circles are 2x and 3x respectively. We can write the ratio as:
Perimeter of Circle 1 : Perimeter of Circle 2 = 2x : 3xFinding the Ratio of Radii
The radius of a circle is half the diameter. Since the circumference of a circle is directly proportional to its radius, the ratio of the radii will be the same as the ratio of the perimeters.
Radius of Circle 1 : Radius of Circle 2 = 2x : 3xFinding the Ratio of Areas
The formula to calculate the area of a circle is given by:
A = πr^2Where A is the area, and r is the radius of the circle.
The ratio of the areas of the two circles will be the square of the ratio of their radii:
Area of Circle 1 : Area of Circle 2 = (2x)^2 : (3x)^2Simplifying the above expression, we get:
Area of Circle 1 : Area of Circle 2 = 4x^2 : 9x^2Area of Circle 1 : Area of Circle 2 = 4 : 9Conclusion
The ratio of the areas of the two circles is 4:9.