plz help If A=(2,1), B=(1,2), C=(3,1) Find the angle ABC using scalar products​

Roger and natalie travel in similar cars. roger's car drives the two miles to school in 7.5 minutes. natalie drives the same distance in the opposite direction but in only 6.5 minutes. what is true of their velocities?

There are 15 plates and each plate is either 7 or 12 inches diameter. which systems of equations do you use to find the number of 7 inch plates, x and 12 inch plates, y

Terri makes a quilt using three sizes of fabric squares the side lenght of each fabric square is the square root of the area