Please help I am really confused with this​

Simplify (1/2)4th power a. (1/16) b.(1/8) c.(1/4)

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

On the first of each month sasha runs a 5k race she keeps track of her times to track her progress her time in minutes is recorded in the table