How do u subtract with mixed numbers?

Suppose the radius of a circle is 16. what issuppose the radius of a circle is 16. what is its circumference its circumference

How to choose the sign of the radical in the denominator of the formula for the distance from a point to a line.

Marla bought a book for $12.95, a binder for $3.49, and a backpack for $44.99. the sales tax rate is 6%. find the amount of tax and the total she paid for these items