Question

Can someone help me with this Geometry problem, please?

Answer 1

Hello from MrBillDoesMath!

Answer:

72

Discussion:

Total Surface area = area of pyramid base + 4 ( area of triangular face)

In our case this becomes

                                 4*4                               + 4(  (1/2) (4)(7) )  =

                                 = 16 + (2)(4)(7)

                                 = 16 + 56        

                                 = 72

which is the first choice.  

Note: the area of a triangular face was computed using (1/2) b h, which in our case is

(1/2) (4) (7)

Thank you,

MrB