Randys bicycle tires have a diameter of 42 centimeters. which is the circumference of one of the tires? use 3.14 for pi

The distance of a chord from the centre of a circle is 12cm and the lenght of the chord is 10cm. find the radius of the circle

Given: ab ≅ bc and ao ≅ oc ok − angle bisector of ∠boc find: m∠aok

Can you me with this question? i'll reward *30 points i just need with this one question so that i could solve the others. * edit: i originally set up the question to reward 30 points, but for some reason i can only reward 15. if you don't get 30, then i'm sorry. i'm still kind of new to this site