Kyle is making a model of an Egyptian pyramid for his history class. Each side of the pyramid he makes has a base of 18.6 cm and height 14.8 cm. Calculate the height of Kyle's pyramid to the nearest tenth of a centimeter.

Don't I need an angle to calculate this? I don't understand

Cut a slice through the pyramid, perpendicular to one of the faces.

You have a right triangle, with the base 18.6/2 and the hypotenuse of 14.8

Now just use the Pythagorean Theorem to find the height.