Adolphin swim 665,280 feet in three hours use formula d= rt where d represents distance r represents rate and t represents time .
a. rearrange distance formula d equals rt to solve for rate
b find the dolphins rate in feet per hour
c find the dolphins rate in miles per hour
d which unit feet or miles makes more sense to use in the scenario and why

if d = rt

then r = d/t

r = 665,280/3

r = 221,760

the dolphins travel 221,760 feet per hour.

1 mile = 5280 feet

221,760/5280 = 42

the dolphins travel 42 miles per hour.

the unit "miles per hour" makes more sense to use in this scenario because the dolphins travel far and at high speed.

a. to solve for rate (r), you must isolate r on one side of the equation. if you have d = rt, divide the entire equation by t. this will leave you with r = d/t.

b. to find the dolphin's rate in feet per hour (ft/h), take the distance (665,280 ft) and plug it into the rate equation we made earlier (r = 665,280/t). we also know that the dolphin swam this far in three hours. if you plug that in also you get r = 665,280/3. 665,280/3 = 221,760, so the dolphin is swimming at a rate of 221,760 ft/h.

c. to translate this to miles per hour (mph), simply divide 221,760 ft by 5,280 ft (the amount of feet in a mile). 221,760/5,280 = 42, so the dolphin swims at 42 mph.

d. mph makes more sense to use in the scenario because of how large the number in feet per hour is. would you rather say/write 42 or 221,760? 221,760 is much too large to use on a movement as fast as this, so 42 mph makes more sense to use.

12cm

the answer is d