Question

va roggggg ajutați mă dau coroană ​

Answer 1

Explicație pas cu pas:

a)

$\mathcal{A}_{dreptunghi} = L \cdot \ell = (4 + \sqrt{7} ) \cdot (4 - \sqrt{7} ) = {4}^{2} - {(\sqrt{7} )}^{2} = 16 - 7 = 9 \ ( {u.m.}^{2} )$

b)

$\mathcal{A_{patrat}} = {\ell}^{2} = {(2a + 5)}^{2} = 4 {a}^{2} + 20a + 25 \ (u.m.^{2})$

c)

$\mathcal{A}_{paralelogram} = \ell_{B} \cdot h_{\ell_{B}} = (a + \sqrt{11} ) \cdot (- a + \sqrt{11} ) = {( \sqrt{11} )}^{2} - {a}^{2} = 11 - {a}^{2} \ (u.m.^{2})$

d)

$\mathcal{A}_{romb} = \dfrac{D \cdot d}{2} = \dfrac{(13 + 2 \sqrt{5}) \cdot (13 - 2 \sqrt{5})}{2} = \dfrac{ {13}^{2} - {(2 \sqrt{5} )}^{2} }{2} = \dfrac{169 - 20}{2} = \dfrac{149}{2} = 74.5 \ (u.m.^{2})$

e)

$\mathcal{A}_{trapez} = \dfrac{(B + b) \cdot h}{2} = \dfrac{(7 - 3 \sqrt{2} + 5 - 2 \sqrt{2} ) \cdot (12 + 5 \sqrt{5} )}{2} = \dfrac{(12 - 5 \sqrt{2}) \cdot (12 + 5 \sqrt{5} )}{2} = \dfrac{144 - 50}{2} = 47 \ (u.m.^{2})$