Answer:
151 cm² (i don't know what unit you were given so im going to use cm)
Explanation:
Part One: finding the missing side (h)
h = a² = b² + c²
13² = 12² + c²
169 = 144 + c²
169 - 145 = c²
= 25
square root of 25 = c
5 = c
area of top triangular area = ½ b × h
= ½ × 12 × 5
= 30 cm²
Part Two
area of rectangle = l × b
= 12 × 8
= 96 cm²
Part Three
area of square = l × l
= 5 × 5
= 25 cm²
total surface area = (30 + 96 + 25) cm²
= 151 cm²