a,b - boki prostokąta
c - bok kwadratu
b = a + 3cm
c = a + 10cm
a*b = c² - 170cm²
Ob_p = ?
a * (a+3) = (a+10)² - 170
a² + 3a = a² + 20a + 100 - 170
3a = 20a -70
17a = 70
a = 70/17
a = 4 2/17 cm
b= 7 2/17 cm
Ob_p = 2 (a+b) = 2 (4 2/17 + 7 2/17) = 2 (11 4/17) = 22 8/17 cm