Question

dau 100 p pt cine le face

Answer 1

1)

d = l√3 = 8√3 => l = 8 cm

V = l³ = (8cm)³ = 512 cm³

2)

d = √(L² + l² + h²)

= √(36 + 108 + 81)

= √225

= 15 cm

3)

Al = 240 = Pb×h

240cm² = Pb×8cm

Pb = 240cm²/8cm = 30 cm

Pb = 30cm = 3×l => l = 30/3 = 10 cm

V = Ab×h

= l²√3×h/4

= 100cm×8cm×√3/4

= 800√3cm²/4

= 200√3 cm²

4)

d = √(l² + h²)

= √(100 + 200)

= √300

= √3×10²

= 10√3 cm

5)

BD' = √(AB²+BC²+AA'²) = √(128 + 64 + 64) = √256 = 16 cm

duc AE ⊥ BD' (AE = d(A;BD'))

ΔABD' = dreptunghic =>

=> AB×AD' = AE×BD'

AE = AD'×AB/BD'

= 8√2×8√2/16 = √2×√2 = 2 cm

6)

AD' ; AC ; CD' = diagonale in patrat =>

AD' = AC = CD' => ΔACD'= echilateral

inaltimea intr-un echilateral este data de formula

h = l√3/2, unde l = latura triunghiului ACD' si in cazul nostru este egala cu diagonala fetelor patratului adica AD' ; AC ; CD'

AC = AB√2 = 12√2 cm

h = 12√2×√3/2 = 6√6 cm

d(C ; AD') = h = 6√6 cm