Mathematics: Please help with any of the 3!

Please help with any of the 3! - id313567490, KennyMckormic

Ответ:

jackolantern1437

30.06.2021

Step-by-step explanation:

(look at the picture)

$a)\\A_{\boxed{\ }}=a\cdot b;\ a=9;\ b=8\\\\A_{\boxed{\ }}=9\cdot8=72\\\\A_\triangle=\dfrac{a\cdot h}{2};\ a=3;\ h=4\\\\A_\triangle=\dfrac{3\cdot4}{2}=\dfrac{12}{2}=6\\\\\huge\boxed{A=72-6=66}$

$b)\\A_{\boxed{\ }}=a\cdot b;\ a=15,\ b=5\sqrt3\\\\A_{\boxed{\ }}=15\cdot5\sqrt3=75\sqrt3\\\\A_\triangle=\dfrac{a\cdot h}{2};\ a=5;\ b=5\sqrt3\\\\A_\triangle=\dfrac{5\cdot5\sqrt3}{2}=\dfrac{25\sqrt3}{2}=12.5\sqrt3\\\\\huge\boxed{A=75\sqrt3-12.5\sqrt3=62.5\sqrt3}$

$c)\\A_{\boxed{\ }}=a\cdot b;\ a=3\sqrt2;\ b=3\\\\A_{\boxed{\ }}=3\sqrt2\cdot3=9\sqrt2\\\\A_\triangle=\dfrac{a\cdot h}{2};\ a=3;\ h=3\\\\A_\triangle=\dfrac{3\cdot3}{2}=\dfrac{9}{2}=4.5\\\\\huge{\boxed{A=9\sqrt2-4.5}}$