The length of the rectangle is 2 times the width, the diagonal of the rectangle is 25 cm. Find the width of the rectangle.

We immediately enter the variable to solve the problem.

Let m be the width of the rectangle, then, according to the conditions of the problem, (2 * m) is its length.

We express the value of the diagonal of the rectangle using the Pythagorean theorem. The diagonal is the hypotenuse of the right triangle, the sides are the legs.

25 ^ 2 = m ^ 2 + (2 * m) ^ 2;

25 ^ 2 = 5 * m ^ 2;

m ^ 2 = 625/5 = 125;

m = 125 ^ (1/2) = 5 * 5 ^ (1/2) cm.