Please answer~ 25 points :p

y=15

Step-by-step explanation:

We know that the angles in a triangle add to 180 degrees

∠ABC+∠BAC+∠ACB=180

We don't know what ∠ACB is, but we know it is on a straight line with another angle (∠ACD). They are supplementary, and must add to 180

∠ACB+ ∠ACD=180

∠ACB+146=180

Subtract 146 from both sides

∠ACB=34

Now, we know ∠ABC is 4y+8, ∠BAC is 5y+3 and∠ACB is 34, so we can substitute them in

∠ABC+∠BAC+∠ACB=180

4y+8+5y+3+34=180

Combine like terms

4y+5y+8+3+34=180

9y+45=180

Subtract 45 from both sides

9y=135

Divide both sides by 9

y=15

step-by-step explanation: h: (- 3, 6)

m: (1, - 2)

o: (7, 6)

r: (- 9, - 2)

midpoint of hm: (- 1, 2)

midpoint of or: (- 1, 2)

therefore, b is the midpoint of both diagonals bisect each other !

to prove the diagonals are perpendicular, show that the product of the slopes = - 1

i think that you should ask google for the answer to that problem because if we don't know it google does