what is the measure of angle 3 ?
a.25
b.35
c.70
d.85

If you look along the downward sloping line you can see that:

85+2x+x-10=180  combine like terms on left side

3x+75=180  subtract 75 from both sides

3x=105  divide both sides by 3

x=35

Now if L and M are parallel, angle 3 must be equal to x-10 because they are vertical angles (equal opposing angles).  We know now that x=35 so:

angle 3 =35-10=25°

Two because two of one thing is two.