The measurements are:
b₁ = 8.4 inches; b₂ = 14 inches; leg₁ = 2.8 inches; leg₂ = 2.8 inches
Let x = length of base and leg
The formula for perimeter of isosceles trapezoid is P = b₁ + b₂ + 2(leg)
Where: b = base
P = b₁ + b₂ + 2(leg)
28 = 3x + 5x + 2(x)
28 = 8x + 2x
28/10 = 10x/10
2.8 = x
Now, substitute the values:
P = b₁ + b₂ + 2(leg)
28 = 3(2.8) + 5(2.8) + 2(2.8)
28 = 8.4 + 14 + 5.6
28 = 28
Hence the measurements are:
b₁ = 8.4 inches; b₂ = 14 inches; leg₁ = 2.8 inches; leg₂ = 2.8 inches
We need to make h alone.
Add 7 to both sides to remove -7 from the right, and multiply both sides by -1 to make h positive. Doesn't matter which you do first.
Result:
6=h
h=6
The answer to your question would be w=9
