Ok so, I have to find the surface area of a triangular pyramid which is, S=B+1/2Pl and so far I've got S=10+1/2(8.7x6.7) which equals 39.145, is this correct? I just want to double check, if not, then I'd really appreciate some help!
clearly, 10+1/2(8.7x6.7)=39.145
But, unless you provide some more information about B,P,I and their relation to the pyramid, it's hard to say whether that is really S.