The cake is in the shape of a circle. How many degrees in a circle?
Abi is 9 years old so the angle of her slice is 9 x 10 = 90°, Elvera is 14 years old so her angle is 14 x 10 = 140°. Total angle used so far is 90° + 140° = 230°. The remaining angle belongs to Tina. 360° - 230° = 130°. Remember that the angle cut is Tina’s age multiplied by 10. (Tina’s Age x 10 = 130). We must divide 130 by 10 to give us Tina’s age. (130/10 = 13) Tina is 13 years old.