The perimeter of the base of a regular triangular prism is 18 cm, the side edge is 10 cm. Find the area of the side face.

A triangular prism is considered correct if its base is an equilateral triangle and its lateral edges make right angles with the planes of the bases.
The side face of a regular triangular prism is a rectangle, one of the sides of which coincides with the side of the base (a), and the other with the side edge of the prism (h).
S = a × h
We know the length of the side edge, so we find the length of the side of the base.
The perimeter of an equilateral triangle must be divided into three to obtain the length of one side:
18 cm ÷ 3 = 6 cm.
S = 6 × 10 = 60cm ^ 2
Answer: 60cm ^ 2.



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