Some More Geometry, please help asap??

These questions all use the same fact.

Opposite angles in a cyclic quadriateral are Supplementary, That means they add up to 180 degrees.

Now you can work all of them out by yourself.

First one :

A + 121  = 180    subtract 121 from both sides

A   = 180  - 121  =  59°

Second one :

(4x + 5)  + (x + 15)  = 180     simplify

5x + 20   = 180      subtract 20 from both sides

5x  = 160      divide both sides by  5

x  = 32

So....A  = (4 * 32 + 5)  =  133°

Third one : 

(6x + 19) + x  = 180

7x + 19  = 180       subtract 19 from both sides

7x  =  161         divide both sides by 

x  = 23

B  = 6*23 + 19   = 157°

Last  one  :

B + D  = 180....so....

3x  + (x + 20)  = 180

4x + 20  = 180       subtract 20 from both sides

4x   =  160           divide both sides by 4

x  = 40

So      A +  C   = 180    ......so....

(2 * 40  +  38 )  + C    = 180

118  + C  = 180           subtract  118 from  both sides

C  = 62°