Find the value of z, angles related to a circle

Find the value of the variable and the length of each chord for #5 and #6.

Eiko is wearing a magic ring that increases the power of her healing spell by 30%30\%30%30, percent. without the ring, her healing spell restores health points. which of the following expressions could represent how many health points the spell restores when eiko is wearing the magic ring?

What is a rule for determining possible values of a variable in a inequality