Question

Cine mă poate ajutaa dau coroniță ​

Answer 1

Explicație pas cu pas:

15.

$Aria= \frac{(AB+DC)× \sqrt{AD²-( \frac{AB - DC}{2} )^{2} } }{2} = \frac{(8+4)\times \sqrt{ {4}^{2} - ( \frac{8 - 4}{2} )^{2} } }{2} = \frac{12 \times \sqrt{16 - 4} }{2} = 12 \sqrt{3} \: {cm}^{2}$

16.

$Aria=2×(3×4+3×5+4×5)=2×(12+15+20)=2×47=94 \: cm^{2}$

17.

$d(O,(VBC))= \frac{\sqrt{VA^{2} - ( \frac{AB \sqrt{2} }{2} )^{2} } \times \frac{AB}{2} }{ \sqrt{VA²-( \frac{AB}{2} )^{2} } } = \frac{ \sqrt{5 \times 16 - 2 \times 16} \times 4}{ \sqrt{5 \times 16 - 16} } = \frac{4 \sqrt{3} \times 4 }{8} = 2 \sqrt{3} \: cm$

18.

$AB=\frac{ \frac{3}{2} \times VA \times \sin(60) }{cos(30) } = \frac{3 \times VA}{2} = \frac{3 \times 4}{2} = 6 \: cm$