+2448 
Do I just add up the measurements that are already there first?
+129852 Hey, RP....good to see you !!!
First one
We have a quadrilateral inscribed in a circle (a cyclic quadrilateral).....whenever this is so....the opposite angles in the quadrilateral are supplementary (the sum to 180°)
So
A + C = 180
A + 101 = 180 subtract 101 from both sides
A = 79°
Smillarly
B + D = 180
B + 68 = 180
B = 180 - 68
B = 112°
+2448 These are all answered so differently. How am I supposed to know which formula to use for each problem?
+129852 Second one
Notice that angle Q intercepts arc PSR
And the measure of this arc= 137 + 41 = 178°
And because angle Q is an inscribed angle intercepting this arc...it measures (1/2)(arc PSR) = (1/2)(178) = 89°
We have a cyclic quadrilateral....R is supplemental to 57° = 180 - 57 = 123°
And S is supplemental to Q = 180 - 89 = 91°
