S = 60cм^2; h = 10; a; (a + 2).
S = (a + a + 2)/2 * h = 60 см^2 ; (a + 1) * 10 = 60; a + 1 = 60/10 = 6 см; a = 6 - 1 = 5 см.
Основание (а + 2) = 5 + 2 = 7 см.