Directions: Use the digits 1 through 9, at most one time each, to fill in the boxes and make THREE true number sentences:

### Hint

How many different angles can be plugged into the sine function to produce 0, 1/2, and 1?

### Answer

Many potential solutions, such as:

sin (9pi / 3) = 0

sin (5pi / 6) = 1/2

sin (1pi / 2) = 1

sin (9pi / 3) = 0

sin (5pi / 6) = 1/2

sin (1pi / 2) = 1

Source: Zack Miller

I think there are many good reasons to teach radians besides preparing kids for Calculus… but even if there weren’t, I might teach kids radians just to do this activity with them. What a perfect blend of simplicity and challenge.