The radius of circle N is 3 inches, and the radius of circle O is 4 inches. What is the radius of circle P whose area is the sum of the areas of circles N and O?

*The formula for the area of a circle is A = πr ^{2}. So, the area of circle N is 3^{2}π = 9π in^{2}, and the area of circle O is 4^{2}π = 16π in^{2}. The area of circle P is 9π + 16π = 25π in^{2}. So, for circle P, we have πr^{2} = 25π → r^{2} = 25 → r = *

**5***inches.*

A small square has side length 7 cm, and a medium square has side length 24 cm. What is the side length of a large square whose area is the sum of the areas of the small and medium squares?

*The formula for the area of a square is A = s ^{2}. So, the area of the small square is 7^{2} = 49 cm^{2}, and the area of the medium square is 24^{2} = 576 cm^{2}. The area of the large square is 49 + 576 = 625 cm^{2}. So, for the large square, we have s^{2} = 625 and s = *

**25***cm.*

The side length of a small equilateral triangle is 10 feet, and the side length of a medium equilateral triangle is 24 feet. What is the side length of a large equilateral triangle whose area is the sum of the areas of the small and medium equilateral triangles?

*The formula for the area of an equilateral triangle is A = s ^{2}√3/4. The area of the small equilateral triangle is 10^{2}√3/4 = 100√3/4 = 25√3 ft^{2}, and the area of the medium equilateral triangle is 24^{2}√3/4 = 576√3/4 = 144√3 ft^{2}. The area of the large equilateral triangle is 25√3 + 144√3 ft^{2} = 169√3 ft^{2}. So, for the large equilateral triangle, we have s^{2}√3/4 = 169√3 → s^{2} = 169 × 4 → s = √(169 × 4) = √169 × √4 = 13 × 2 = *

**26***cm.*

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