Question

Find the width of the rectangle with a length of 16 cm. the rectangle is inside the circle with a radius of 10 cm

Answer 1

Assuming you mean the rectangle is inscribed in the circle (all four corners on the circle), the diagonal of the rectangle is the diameter of the circle. So,

w^2 + 16^2 = 20^2

(Think of a 3-4-5 right triangle)