The area of a circle is 4​ pi square kilometers. what is the radius?

Look at triangle wxy what is the length (in centimeters) of the side wy of the triangle?

Me i’m stuck on all these questions besides the two bottom ones

Josie buys a pair of boots that retail for $52.00 dollars, however they are currently on sale for 25% off how much does josie pay for the boots if there is also a 6% sales tax on them