Can someone explain how to do this for me!

x = 90 degrees

Step-by-step explanation:

the above figure is of a circle, so the sum of the measures of angles will be 360 degrees.

measure of arc = measure of the angle inscribed by the arc

therefore, the measure of arc JK will also be x ( vertically opposite angles)

therefore, x + x + 30 + (2x - 30) = 360 (1)

therefore, 2x + 30 + 2x - 30 = 360

therefore, 4x = 360( as -30 and +30 will be cancelled)

therefore, x = 90 degrees

Cross correction:-

by putting in x = 90 in (1)

90 + 90 + 30 + 2*90 - 30 = 360

180 + 30 + 180 - 30 = 360

180 + 180 = 360

so, x= 90 degrees is verified.

the answer is 510

step-by-step explanation:

15 • 13 = 195

15 • 12 = 180

15 • 5 = 75

12 • 5 = 60

195 + 180 = 375

375 + 75 = 450

450 + 60 = 510