Question

1)Intr-un con circular drept inaltimea este egala u 12 cm si diametrul bazei are lungimea de 18 cm.
a) Calculati aria bazei conului.
b)Aflati aria laterala a conului

2) x³-9x (descompus)

Answer 1

R=18:2=9
Abazei=πR²=36π cm²

g=√12²+9²=√(144+81)=√225=15 cm
Alaterala =πRg=π×9×15=135π

2. x³-9x=x(x²-9)=x(x-3)(x+3)

Answer 2

R=9 cm
h=12 cm => G=15 (9,12,15 numere pitagorice)
Ab=$\pi R^{2}=81 \pi$ cm^2
Al=$\pi RG=135 \pi cm^{2}$

$x^{3}-9x=x( x^{2} -9)=x(x-3)(x+3)$