A is equal to 87 degrees. You get this answer since all triangle angle measurements must equal 180 when combined. So you add
36+57=93
180-93=87
A=87
The problem is that 7^2 is 7*7, and the same for 8^2. The right answer is the square root of 15, or 3.87
You find the area of one side of the cube which is 12.25 mm and multiply it by the number of side which is 6. and the answer is 73.5 mm
It is a bit tedious to write 6 equations, but it is a straightforward process to substitute the given point values into the form provided.
For segment ab. (x1, y1) = (1, 1); (x2, y2) = (3, 4).
... x = 1 + t(3-1)
... y = 1 + t(4-1)
ab = {x=1+2t, y=1+3t}
For segment bc. (x1, y1) = (3, 4); (x2, y2) = (1, 7).
... x = 3 + t(1-3)
... y = 4 + t(7-4)
bc = {x=3-2t, y=4+3t}
For segment ca. (x1, y1) = (1, 7); (x2, y2) = (1, 1).
... x = 1 + t(1-1)
... y = 7 + t(1-7)
ca = {x=1, y=7-6t}