Answer:
a² + b² = 15² = 225
P = 2a + 2b = 2(a + b) = 38
P² = 4(a + b)² = 38²
4(a² + 2ab + b²) = 1444
Substitute a² + b² with 225
4(2ab + 225) = 1444
2ab + 225 = 361
2ab = 136
ab = 68 cm²