It's a 3rd grade problem in addition and subtraction, or number lines. As a college-level problem, it might be described as ...
... a part-whole problem, because the length of the third table is part of the total length of the long table
Abc=de
Divide by ab on both sides to get c by itself and find the answer.
c = (de)/(ab)
The angle of YWZ is equal to the angle of YWX, and angle WYX is also a right angle due to the congruency of segments WZ and WX.
Every triangle has an angle total of 180 degrees, so angle WXY is equal to
180 - (WYX + YWX)
180 - (90 + 17)
73
Angle WXY has an angle value of 73 degrees.
To solve this, first we calculate all the total cost of
the items that is:
total cost = $14.96 + $19.87 + $5.37
total cost = $40.20
So we see that the actual cost is similar with the
estimate so his calculation is reasonable.