What did I do wrong in part c? Please correct it and give me the right answer for part c!

IVET IVE TILIS A battery with emf & and no internal resistance supplies current to the circuit shown in the figure below. When the double-throw switch S is open as shown in the figure, the current in the battery is I. When the switch is closed in position a, the current in the battery is Ia. When the switch is closed in position b, the current in the battery is It. (Use the following as necessary: &for &, Ia, I, and I.) R1 RZ R2 & + 26 2R3 A (a) Find the resistance of R1. 28 28 + Ry = I Ib (b) Find the resistance of R2. 28 28 R 2 (c) Find the resistance of R3. 28 R 3 = Ia X