How tall is 21 hand horse in feet?

* One hand equals 4 inches.

* There are 12 inches in a foot.

Calculations:

1. Convert hands to inches: 21 hands * 4 inches/hand = 84 inches

2. Convert inches to feet: 84 inches / 12 inches/foot = 7 feet

Therefore, a 21-hand horse is 7 feet tall.