-4=-1b-(1/3)b
-4=-(4/3)b
-4/-(4/3)=b
b=3
-------------------------------
(1/2)3+(5/3)2
3/6+10/6=13/6
-23/3=13/6a
(-23/3)/(13/6)=a
a=-46/13
Cos60° = 0.5
Any angle less than 90° is an acute angle.
Therefore, 60° is the acute angle.
Since CM is perpendicular to AB, it follows that ∠1 and <span>∠2 are 90 degrees. Since they both have 90 degree angles, that must mean they are both right triangles.
And since </span>∠3 = ∠4 and ∠1 = ∠2, then it follows that ∠A = <span>∠B. (You can show this by showing that they must add up to 180 degrees.)
So since both right triangles have 3 congruent angles to each, then that makes them similar by AAA (angle angle angle).</span>
