Answer:
450
Step-by-step explanation:
Length = l
Breadth = b
l = 15 + b
Perimeter = 90
Perimeter = 2(l + b)
90 = 2(15 + b + b)
90 = 2(15 + 2b)
90 = 30 + 4b
90 - 30 = 4b
60 = 4b
60/4 = b
15 = b
Hence, l = 15 + 15 = 30
Area = l * b
Area = 30 * 15
Area = 450 unit²
