Question

How to solve #12 can't seem to figure it out after spending 20 mins on it

Answer 1

The area of one of the triangular lateral faces is


`\frac{401.48-166.28}6=39.2`

You're told that the slant height, which is the same as the height of the triangular face, is 9.8, so you have


`39.2=\frac12*9.8* b`

where
`b` is the length of the base of the triangle, which is also the same as the side length of the base of the pyramid. So


`b=8`