What is the arc measure of ABC in degrees?
(20y - 11)
(4y+6) P.
hy-7)

The answer would be 64.

This is because if you notice each pattern is a multiple of the next natural number.

The first patter is 1 dot (the multiple is 1 x 1)

The second pattern is 4 dots (the multiple is 2 x 2)

The third pattern is 9 dots (the multiple is 3 x 3)

The fourth pattern is 16 dots (the multiple is 4 x 4)

The fifth pattern would be 25 dots (the multiple would be 5 x 5)

The sixth pattern would be 36 dots (the multiple would be 6 x 6)

The seventh pattern would be 49 dots (the multiple would be 7 x 7)

The eight pattern would be 64 dots (the multiple would be 8 x 8)

Hope this is a good explanation.