The base of the straight prism is a triangle with sides of 8cm and 15cm and an angle between them of 60 degrees.

The base of the straight prism is a triangle with sides of 8cm and 15cm and an angle between them of 60 degrees. The height of the prism is 11cm. Find the lateral surface area.

S side surface = P base * height.
The height is given, so we find P of the base.
P base is equal to the sum of all sides. But we are missing the meaning of one side. Let’s find it through the cosine theorem:
a ^ 2 = 8 ^ 2 + 15 ^ 2-2 * 8 * 15 * cos60 = 64 + 225-2 * 8 * 15 * 0.5 = 289-120 = 169
a = 13
Hence, the third side is 13. Now we find the P base:
P = 13 + 15 + 8 = 36
S lateral surface area = 36 * 11 = 396
Answer: 396