1 foot= 12 inches
STEP 1
Multiply 3 feet by 12 inches per foot
= 3 feet * 12 inches per foot
= 36 inches
STEP 2
Add inches in 3 feet with the additional 11 inches
= 36 inches + 11 inches
= 47 inches
ANSWER: Ian is 47 inches tall so he is not tall enough to ride.
Hope this helps! :)