The coordinates for D are (-4, -7)
First we must locate point B as it is vital to finding the midpoint of BD. To do this, we take the average of the endpoints AC since B is its midpoint.
x values = -9 + 1 = -8
Then divide by 2 for the average -8/2 = -4
y values = -4 + 6 = 2
Then divide by 2 for the average 2/2 = 1
Therefore B must be (-4, 1)
Now we know the values of E must be the average of B and D. So we can write equations for each coordinate since we know they are averages.
x - values = (Bx + Dx)/2 = Ex
(-4 + Dx)/2 = -4 ---> multiply both sides by 2
-4 + Dx = -8 ---> add -4 to both sides
Dx = -4
y - values = (By + Dy)/2 = Ey
(1 + Dy)/2 = -3 ---> multiply both sides by 2
1 + Dy = -6 ---> subtract 1 from both side
Dy = -7
So the coordinates for D must be (-4, -7)
To best estimate the volume of the log, we assume that the diameter is the average of the diameters at both ends giving us 12 inches as the diameter. Thus, the radius is equal to 0.5 ft. The volume of the log is calculated through the equation,
V = πr²h = π(0.5 ft)²(10 ft) = 7.85 ft³
