1.5,3,4.5,6,...arithmetic sequence or geometric sequence

Step-by-step explanation:

1.5 , 3 , 4.5 , 6  

This is an arithmetic sequence. Each term is obtained by adding 1.5 to the previous term.

First term = 1.5

Common difference = second term - first term

                                 = 3 - 1.5 = 1.5

Check:

Second term = 1.5 + 15 = 3

Third term = 3 + 1.5 = 4.5

Fourth term = 4.5 + 1.5 = 6

3x + 18 = 147°

step-by-step explanation:

3x + 18 = 147°, because the value of the central angle is equal to the value of the arc formed by it.

i hope i you.