1. **Problem Statement:** Find the average height of Geoff and his two brothers given their heights: Geoff is 18'3", brother 1 is 17'10", and brother 2 is 17'11". 2. **Formula:** The average height is given by $$\text{Average} = \frac{\text{Sum of all heights}}{\text{Number of individuals}}$$ 3. **Convert heights to inches:** - Geoff: $18'3" = 18 \times 12 + 3 = 216 + 3 = 219$ inches - Brother 1: $17'10" = 17 \times 12 + 10 = 204 + 10 = 214$ inches - Brother 2: $17'11" = 17 \times 12 + 11 = 204 + 11 = 215$ inches 4. **Sum the heights:** $$219 + 214 + 215 = 648$$ inches 5. **Calculate the average in inches:** $$\frac{648}{3} = 216$$ inches 6. **Convert average back to feet and inches:** - Feet: $\frac{216}{12} = 18$ feet - Inches: $\cancel{\frac{216}{12}} = 18$ with remainder $0$ inches 7. **Final answer:** The average height is **18 feet 0 inches**.