Question

What is the formula for finding the surface area of a regular triangular pyramid?(1 point)
Responses

SA=lw+1/2w+√4h2 +l2 +1/2l√4h2+w2

cap s cap A is equal to l w plus 1 half w square root of 4 h squared plus l squared end root plus 1 half l square root of 4 h squared plus w squared end root - no response given

SA=1/2ab+3(1/2lb)

cap s cap A is equal to 1 half A b plus 3 times open paren 1 half pounds close paren - no response given

SA=2(wl+lh+hw)

cap s cap A is equal to 2 times open paren w l plus l h plus h w close paren - incorrect

SA=a2+2a√a2/4+h2

Answer 1

The correct choice is
SA = 1/2·a·b + 3(1/2·l·b),
which simplifies to SA = (1/2)ab + (3/2)lb.

(Meaning: surface area = area of the triangular base + area of the three congruent lateral triangles. If the base is equilateral with side a and the pyramid altitude is h, use
SA = (√3/4)a^2 + (3a/2)·√(h^2 + a^2/12).)