Step-by-step explanation:
l = length
w = width
l = 3w
perimeter p = 2l + 2w = 56
using the identity of the first equation
p = 2(3w) + 2w = 56
6w + 2w = 56
8w = 56
w = 7 cm
l = 3w = 3×7 = 21 cm
so, the area is
l×w = 21×7 = 147 cm²
Answer:
20
Step-by-step explanation:
25^2=15^2+x^2. x=20
