Find the perimeter of a regular dodecagon whose vertices are twelve equally spaced points on the unit circle.

Find the solution of this system of equation -7x+y=-20 9x-3y=36

Expresa commuter train leaves downtown sation and travels at a average speed of 55 miles per hour towards the north side sation, which is 50miles away. thirty minutes later, express commuter train #7 leaves north side and travels at a average speed of 35miles per hour towards downtown sation. at the moment the two trains pass each other, how far(in miles) is train #12 from the downtown sation and how long(in minutes) has the #12 train been traveling

Do,h = (7, 9) (14, 18) the scale factor is