Please help me solve for this don't report I did NOT ignore the Honor rule

In the diagram, ab is tangent to c, ab = 4 inches, and ad = 2 inches. find the radius of the circle.

Jessa bought a yoyo from a company that claims that, with each retraction, the string rolls up by 60% of the original length. she sets up a tape measure and throws the yoyo 3 times. her data are charted below. throw length of string (feet) 1 3 2 1.8 3 1.08 jessa wants to find the sum of the length of string after 10 throws. what is the sum of the lengths, rounded to the nearest hundredth?

Ashop has a sale that offers 20% off all prices. on the final day they reduce all the sale prices by 25% linz buys a ratio on the day. work out the overall percentage reduction on the price of the ratio