Question 171590
Geometry involves a lot of picturing things in your head
(1) Imagine these lines laid one on top of the other.
The difference in their lengths is {{{7 - 5 = 2}}}
Now hold the end where they both start fixed. Rotate
the smaller line very slightly. You've got a triangle
that is something like 7, 5, 2.0001
In order to have a triangle at all, the 3rd side has to
be greater than {{{2}}}
Now keep the point where they meet fixed and rotate the
smaller line until it's directly opposite from where it
started (180 degree rotation). Now rotate the smaller line
very slightly backwards. Now you have a triangle that looks
like 7,5, 11.999
From this you see the 3rd side has to be less than {{{12}}}

(2) Sorry, don't have time
(3) Stated wrong. Inches is not a measure of an angle
Angles are measured in degrees