A circle is inscribed in the trapezoid. Find the radius of the circle if the lateral side is divided by the point
A circle is inscribed in the trapezoid. Find the radius of the circle if the lateral side is divided by the point of tangency into segments a, b.
Let’s connect point O, the center of the circle, with points A and B on the side of the trapezoid. By the property of the trapezoid into which the circle is inscribed, the triangle AOB is rectangular with a right angle at the point O.
From point O we draw the radius OH to the point of tangency of the circle with the lateral side AB. By the property of a tangent, the radius of a circle drawn to the tangent point is perpendicular to the tangent. Then in a right-angled triangle ABO, segment OH, there is a height drawn from a right angle to the hypotenuse, which means OA ^ 2 = AH * BH = a * b.
ОА = √ (a * b) see.
Answer: The radius of the circle is √ (a * b) cm.