Answer:
We use Pythogorus' theorem
[tex] {a}^{2} \: + {b }^{2} \: = {c}^{2} \\ {12}^{2} + {b}^{2} = {13}^{2} \\ 144 + {b}^{2} = 169 \\ {b}^{2} = 169 - 144 \\ {b}^{2} = 25 \\ \sqrt{b} \: = \sqrt{25} \\ b = 5 \\ therefore \: the \: base \: is \: \: (5 + 5) \\ = 10cm \\ perimter \: = s + s + s \\ =( 13 + 13 + 10)cm \\ = 36cm \\ area = \frac{1}{2} \times b \times h \\ \: = \frac{1 \times 10 \times 12}{2} \\ = \frac{120}{2} \\ = 60cm[/tex]
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