Question

5 dau coroana......pls.....la matematică.​

Answer 1

Răspuns:

a)

$P=12\\A=9$

b)

$P=20\\A=25$

Explicație pas cu pas:

a)

$A(0,~2)\\B(\sqrt{5},~0)$

$AB=\sqrt{(0-\sqrt{5})^2 + (2-0)^2}\\AB=\sqrt{\sqrt{5}^2+2^2}\\AB=\sqrt{5+4}\\AB=\sqrt{9}\\AB=3\\\\P=AB\cdot4\\P=3\cdot4\\P=12\\\\A=AB^2\\A=3^2\\A=9$

b)

$A(4,~1)\\C(9,~6)$

$AC=\sqrt{(4-9)^2+(1-6)^2}\\AC=\sqrt{(-5)^2+(-5)^2}\\AC=\sqrt{25+25}\\AC=\sqrt{25\cdot2}\\AC=5\sqrt{2}$

$\text{Fie AB latura p\u{a}tratului.}$

$\left \substack{AC~\text{diagonal\u{a}}\\AC=5\sqrt{2}} \right \} \Rightarrow AB=\frac{\text{diagonala}}{\sqrt{2}}\\\Rightarrow AB=\frac{5\sqrt{2}}{\sqrt{2}}\\\Rightarrow AB=5$

$P=AB\cdot4\\P=5\cdot4\\P=20$

$A=AB^2\\A=5^2\\A=25$