Question is not stated clearly
Answer:
Value of y = 7
Step-by-step explanation:
By the midpoint theorem of the triangles,
"Segment joining midpoints of the two sides of a triangle is parallel to the third side and measure half the length of the third side."
Therefore, from the figure attached,
In ΔFGH,
J and K are the mid points of the two sides GH and FH.
By theorem, segment JK║GF and m(JK) = 

(5y + 3) = 2(2y + 5)
5y + 3 = 4y + 10
5y - 4y = 10 - 3
y = 7
Answer:
A is f(t)=-(t-4)^2+50
B is 50. the top of the graph is at 50
C is at 4. that is the x value when y=50
If you need the graph put the answer from question A into Desmos
The radius is 8
Im not sure if this is what your looking for