Question

preciso disso urgente​

Answer 1

Resposta:

Explicação passo a passo:

$4)$

$A=16,15\:cm^{2}$

$b=2\:cm$

$B=8\:cm$

$h=?$

$A=\frac{(B\:+\:b\:)\:.\:h}{2}$

$16,15=\frac{(8\:+\:2\:)\:.\:h}{2}$

$5h=16,15$

 $h=\frac{16,15}{5}$

 $h=3,23\:cm$

$5)$

$a)$

$A=28\:cm^{2}$

$b=5\:cm$

$B=x+3$

$h=6\:cm$

$A=\frac{(B\:+\:b\:)\:.\:h}{2}$

$28=\frac{(x+3\:+\:5\:)\:.\:6}{2}$

$28=\frac{(x+8\:)\:.\:6}{2}$

$28=3\:.\;(x+8)$

$3x+24=28$

$3x=28-24$

$3x=4$

$x=\frac{4}{3}\:cm$

$b)$

$B=x+3$

$B=\frac{4}{3}+3$

$B=\frac{4}{3}+\frac{9}{3}$

$B=\frac{13}{3}\:cm$