The cost of chartering a bus for the great america trip was split evenly by the 20 students planning to go. The day before the trip, 10 more students decided to go. dividing the cost evenly among all 30 students brought the average cost down by $9.00 per person. What was the total cost of chartering the bus?

Okay so for every triangle has three angles that always add up to 180 degrees. and to tell the difference between whether they are secure, right or obtuse is that acute: has one angle that is less than 90 degrees. right triangle means there is at least one angle that is exactly 90 degrees. and an obtuse angle has an angle that is bigger than 180 degrees. i’ll do #13 as an example: 13. 40 and 50 so if every triangle has 180 degrees 40+50= 90 degrees then180-90= 90 degrees so the third angle is 90 degrees and because this triangle has a 90 degree angle it means it is a right triangle