The side of the base of a regular triangular prism is 4 cm, and the side edge is 2√3. how to find the volume?
1. Known rule of Heron for calculating the area of a triangle on its three sides:
S triangle = {P * (p – a) * (p – b) * (p – c)} ^ 1/2 <where p = (a + b + c): 2.
2. The volume V of the prism is equal to the product of the area of its base by the height.
3. Let’s calculate what is the area S of a regular triangle at the base of the prism, if each side of it is 4 cm.
To do this, we first find the semiperimeter p of the triangle.
p = (4 cm + 4 cm + 4 cm): 2 = 6 cm.
S = (6 * 8 * 8 * 8) ^ 1/2 = (48 * 8 ^ 2) ^ 1/2 = 8 * (16 * 3) ^ 1/2 = 8 * 4 * 3 ^ 1/2 =
32 * 3 ^ 1/2.
4. Let us calculate what the volume V of the prism is equal to if, according to the condition of the problem, the lateral edge H
equals 2 * 3 ^ 1/2 cm.
V = S * H = 32 * 3 ^ 1/2 * 2 * 3 ^ 1/2 = 64 * 3 = 192 cm ^ 3.
Answer: The volume of the prism is 192 cubic centimeters.