If we're talking about a box with dimensions 10 ft, 19 ft and 20 ft, it's probable that the instructions say to calculate the volume. That would be
V = (10 ft)(19 ft)(20 ft) = 3800 cubic feet.
I'm not good at graphing, but desmos.com is an online graphing calculator that works really well.
First we know that,
3x+15=5x-65 because of vertical angle thr.
y=y because of reflex property
there are 360 degrees in a circle so..
3x+15+5x-65+2y=360
3x+15=5x-65
x=40
so each 2 of the angles are...(40*3+15)=135
Then your new equation is
135+135+2y=360
2y=90
<u>y=45</u>
Hope this helps :)