Question

alguem me ajuda com a 7 e 8 pelo amor de Deus ???

Answer 1

S=1/2.5.8.sen30° 
S=1/2.40.1/2 
S=1/4.40 
S=40/4 
S=10 cm² 

Answer 2

$a)40^{2} = x^{2} + x^{2} ~~~~~~~~~~~~~~~b) A= 60.20 \sqrt{2}~~~~~~~~~~~c) A_{\Delta}= \dfrac{20 \sqrt{2}.20 \sqrt{2} }{2} \\ 2 x^{2} =1600 ~~~~~~~~~~~~~~~~~~~~~~~A=1200 \sqrt{2} cm^{2} \\ x= \sqrt{800} = \sqrt{2.400}~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ A_{\Delta}= \dfrac{400.2}{2}=400cm^{2} \\x=20 \sqrt{2}cm \\ \\ \\ \\ \\ \\ \\ .$