The area of a square is 49cm^2. The perimeter of this square is equal to the circumference of a circle. Calculate the radius of the circle to 1 decimal place.

To calculate the perimeter (the length of the outside edge) of a square, you must add up the length of each side. Here, we have been given the area of the square. The area of a square is calculated by squaring (multiplying by itself) the length of one side. Therefore, to find the length of one side in this question, we must find the square root of the area. The square root of 49 is 7.

Our next step is to calculate the perimeter of the square. This is the sum of the length of all four sides and is therefore equal to 4 x 7 which is 28. We have been told that the perimeter of the square is equal to the circumference of the circle and therefore the circumference of the circle is 28. The question has asked us to calculate the radius of the circle, which we can do using the known circumference. The circumference of a circle is equal to 2πr, where π is a constant (take π to equal 3.14) and r is the radius of the circle.

Therefore; 2πr = 28 πr = 28/2 = 14 r = 14/3.14 = 4.45859… To 1 d.p. = 4.5 cm