Question

Un cub care are muchia 2 cm.Aflati Aria totala,volumul si diagonala cubului

Answer 1

V = l³ = 2³ = 8 cm³
d = l√3 = 2√3 cm
At = 6Ab
Ab = l² = 2² = 4 cm²
At = 6 · 4 = 24 cm²

A doua problema

ABCDA'B'C'D' prisma triunghiulara

Fetele patrat ==> AB = BB' = B'A' = AA' = √2 cm

Al = Pb · h
Pb = 3l = 3AB = 3 · √2 = 3√2 cm
Al = 3√2 · √2 = 3·2 = 6 cm²
V = Ab · h
Ab = $\frac{ l^{2} \sqrt{3} }{4} = \frac{ AB^{2} \sqrt{3} }{4} = \frac{ \sqrt{2} ^{2} \sqrt{3} }{4} = \frac{2 \sqrt{3} }{4} = \frac{ \sqrt{3} }{2}$
V = $\frac{ \sqrt{3} }{2}$ · √2 = $\frac{ \sqrt{6} }{2}$

Answer 2

At=6*l^2=6*4=24
V=l^3=2^3=8
diagonala=2 radical 3 cm