Knowing that GB is 18 and CD = 21 you should be able to use them to solve this problem.

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FG = 9BF = 27GD = 7CG = 14

Step-by-step explanation:

Point G is the intersection of medians, the centroid. That point divides each median into parts with a 2:1 ratio. The "2" part is the distance between the centroid and the vertex. The "1" part is the distance between the centroid and the side.

  FG : GB : BF = 1 : 2 : 3 = 9 : 18 : 27 . . . . . where 18 is given

  GD : CG : CD = 1 : 2 : 3 = 7 : 14 : 21 . . . . . where 21 is given

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