Ally is making a scale diagram of her classroom. She uses a scale factor of 3 centimeters per foot to draw the diagram. The actual length of the classroom is 18 feet, and its width is 20 feet. What is the area of the scale drawing of the classroom? A.
54 square centimeters
B.
60 square centimeters
C.
360 square centimeters
D.
3,240 square centimeters

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