There is a roll of two triangular, pyramids, and one pentagonal pyramid, and a display at a museum. How many lateral faces are there altogether?

1 answer

To find the total number of lateral faces on the three pyramids, we need to add together the number of lateral faces on each pyramid.

A triangular pyramid has 3 lateral faces.
So, two triangular pyramids have a total of 2 * 3 = <<2*3=6>>6 lateral faces.

A pentagonal pyramid has 5 lateral faces.

Therefore, the two triangular pyramids and one pentagonal pyramid have a total of 6 + 5 = <<6+5=11>>11 lateral faces altogether. Answer: \boxed{11}.