#### Answer

P=15+5$\sqrt 3$$\approx$23.66

#### Work Step by Step

An inscribed angle with a measure of 90 degrees intercepts a diameter of the circle. If the radius is 5 cm then the hypotenuse of the triangle is equal to 10 cm. Since it is a 30 60 90 triangle, the short leg is equal to 5 cm and the long leg is equal to 5$\sqrt 3$ cm.
P=10+5+5$\sqrt 3$
P=15+5$\sqrt 3$$\approx$23.66