Answer:
Step-by-step explanation:
Volume of pyramid = 1
3 × base area × height
180 = 1
3 × 10 × 8 × height
180 = 80
3 × height
Height = 6.75 cm
part two
Let the slant height from V to PQ be l1 cm,
the slant height from V to QR be l2 cm.
Using Pythagoras’ Theorem,
l1 = square root(6.75^2 + 4^2) = 7.846 (to 4 s.f.)
l2 =square root(6.75^2 + 5^2)= 8.400 (to 4 s.f.)
Total surface area of pyramid
Area of all triangular faces + area of square base
2 (1/2*10*7.846+1/2*8*8.400)+10*8
2(39.23 + 33.6) + 80
145.66 + 80
226 cm2 (to 3 s.f.)
