The height of a regular triangle is 120. Find the radius of the circle circumscribed about this triangle.

Since triangle ABC is, by condition, regular, its height is also the median of the triangle.

The point of intersection of the medians is the center of the inscribed and circumscribed circle around the triangle, and divides the median in the ratio of 2/1.

Then OB = 2 * OH.

ОВ + ОН = ВН = 120 cm.

2 * OH + OH = 120.

3 * OH = 120.

OH = 120/3 = 40 cm.

Then ВO = R = ВН – VO = 120 – 40 = 80 cm.

Answer: The radius of the circumscribed circle is 8 cm.