we can't solve first 2 because of missing diagramd
but, longest side=hypotonuse=c
other 2 sides=legs=a and b
a^2+b^2=c^2
\(\sqrt{a^{2}+b^{2}}=c\)
last 2
1.
remember that
longest side<sum of other 2 sides or else you can't make a traignel
5+7=12
12<13
13 is longest side
13<12 is false
therefor it is false that it is a triangle
not a triangle
2.
\(\sqrt{ \frac{x}{y} } = \frac{ \sqrt{x} }{ \sqrt{y} }\) so
\(\sqrt{ \frac{20}{7} } = \frac{ \sqrt{20} }{ \sqrt{7} }\) =\(\frac{4\sqrt{5} }{\sqrt{7} }\)
rationalize denomeator by multplying by \(\frac{ \sqrt{7} }{ \sqrt{7} }\)
\(\frac{4\sqrt{35} }{7}\)
