a)
[tex]a = 5 \ cm\\b = h = 12 \ cm\\c = 13 \ cm\\\\P = \frac{1}{2}ah} = \frac{1}{2}ab= \frac{1}{2}\cdot5 \ cm\cdot12 \ cm = 30 \ cm^{2}\\\\Ob = a+b+c = 5 \ cm + 12 \ cm + 13 \ cm = 30 \ cm[/tex]
b)
[tex]a = 60 \ mm = 6 \ cm\\b=h = 8 \ cm\\c = 1 \ dm = 10 \ cm\\\\P = \frac{1}{2}ab = \frac{1}{2}\cdot6 \ cm\cdot8 \ cm = 24 \ cm^{2}\\\\Ob = a+b+c = 6 \ cm + 8 \ cm + 10 cm = 24 \ cm[/tex]
c)
[tex]a = 15 \ mm = 1,5 \ cm\\b=h = 2 \ cm\\c = 2,5 \ cm\\\\P = \frac{1}{2}ab = \frac{1}{2}\cdot1,5 \ cm\cdot2 \ cm = 1,5 \ cm^{2}\\\\Ob = a+b+c = 1,5 \ cm + 2 \ cm + 2,5 \ cm = 6 \ cm[/tex]
d)
[tex]a = 80 \ mm = 8 \ cm\\b = h = 15 \ cm\\c = 17 \ cm\\\\P = \frac{1}{2}ab = \frac{1}{2}\cdot8 \ cm\cdot15 \ cm = 60 \ cm^{2}\\\\Ob = a+b+c = 8 \ cm + 15 \ cm + 17 \ cm = 40 \ cm[/tex]
