Stanley drove his car on a business trip when he left the mleage was 840miles. and. when he returned the mileage was 1,200miles. the car used 12 gallons of gasoline for this trip

I think for this item, the rate at which the gasoline was consumed is to be calculated. To determine the distance that Stanley's car had traveled, we subtract 840 miles from 1,200 miles. That will give us an answer of 360 miles. Dividing this by 12 gallons will give us an answer of 30 miles/gal. 

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