Answer:
β = arccos((a^2 + c^2 - b^2)/(2·a·c))
β = arccos((3^2 + 7^2 - 5^2)/(2·3·7)) = 38.21°
Percent change: (new value - old value)/old value * 100
((10-2.50)/2.50) = 3 * 100 = 300%
There is a 300% increase
No he actually got slower. if you divide 198\6 it equals 33 if you divide 248\8 you get 31
(3-8y) x (-2.5)
= -7.5+20y
