Is line AC tangent to circle O?

The sum of two numbers is 86, and their difference is 20. find the two numbers

What is the y intercept of f(x)=(1/2)^x?

Fred has a spinner that is split into four equal sections: red, blue, green, and yellow. fred spun the spinner 688 times. which of the following would be a good estimate of the number of times the spinner lands on the green section? a. 269 b. 603 c. 344 d. 189