Zadanie
a = x
b = 2x
d = 4√5
a² + b² = d²
x² + (2x)² = (4√5)²
x² + 4x² = 80
5x² = 80 l :5
x² = 16
x = √16
x = 4
a = x = 4
b = 2x = 2 · 4 = 8
P = a · b
P = 4 · 8 = 32 (j²)
Ob. = 2 · a + 2 · b
Ob. = 2 · 4 + 2 · 8 = 8 + 16 = 24 (j)
