Question

The area of a circle is twice the sum of the areas of three circles with radii 2 cm, 3 cm 6 cm. Find the radius of this circle?

Answer 1

Ответ:

Find the areas of 3 circles

The area of the circle is found by the formula πr²

S₁=4π

S₂=9π

S₃=36π

Sum of 3 squares=49π

And the area of the great circle is twice as large, therefore it is equal to 49π*2=98π

S=πr²

98π=πr²

r²=98

r=7$\sqrt{2}$