The diameter of a circle is 36 centimeters. Find the radius

Which of these people has balanced their checkbook correctly? oa. gary: the balance in his check register is $500 and the balance in his bank statement is $500. b. gail: the balance in her check register is $400 and the balance in her bank statement is $500. c. gavin: the balance in his check register is $500 and the balance in his bank statement is $510.

Show your workcan a right triangle have this sides? *how to prove it without using the pythagorean theorema*

Math it's appreciated. (picture provided)