I only need 4: Find the radius of circle G below.
Hint: AT = AM because ED is a perpendicular bisector. Whenever a chord intersects and forms a right angle, then one of them is a perpendicular bisector.
You can also use the theorem that says that MA·AT = EA·AD
---> 9·9 = 4·AD
---> AD = 81/4
---> AD = 20.25
Find the diameter and divide by 2.