Answer:
I think these should help.
Step-by-step explanation:
If the 3 is supposed to be replaced by any x's, then the answer would be 29 I believe.
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
Out of the 3 points, only ABC are collinear. Hence, only ABC can be chosen. The chances of choosing ABC out of ABCD is 1/4. Hence, the probability is 25%.