Question

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Answer 1

a) VABC = piramida    VO = inaltimea

se duce VM_|_AB  si CM_|_AB

inΔ VOM    OM = 1/3 ·CM = 1/3 ·3√3/2 = √3 /2 cm

in ΔVAB  VM² = VA² - AM² = 4 - 9/4 = 7/4    

VO² = VM² - OM² = 7/4 - 3/4 = 1    VO = 1cm

b)  V = Ab ·h / 3 = L²√3 / 4 ·1/3 = 3√3 / 4 cm²

c)  At = Al + Ab = Pb·ap/2 + L²√3 /4 = 9·√7 /2 ·1/2 + 9√3 /4 ≈ 5,95 +3,897 ≈9,85cm²

ptr. 100 bomboane A≈985cm² >960 cm²