Answer:
4
Step-by-step explanation:
The angle of impact is 30°
<h3>What is the angle of impact?</h3>
In a bloodstain, the angle of impact can be used to determine the appearance of the resulting bloodstain if the bloodstain has a tail or pattern.
- Bloodstain pattern analysis is the study of bloodstains at a scene of the crime in an attempt to reconstruct the events that resulted in the bloodshed.
Mathematically;



Learn more about the angle of impact here:
brainly.com/question/19423063
Edit to reflect comments:
3^-1=1/3
4^-1=1/4
Flip the fraction over basically i.e. 4/1---->1/4
Do you have the answer options? Sorry, can't answer without them ):
Vertex aka max or min point is found by -b/2a in form
f(x)=ax^2+bx+c
f(x)=-1x^2+8x+20
vertex x value is -8/(2)(-1)=-8/-2=4
input back to find y value
f(4)=-(4^2)+8*4+20
f(4)=-16+32+20
f(4)=36
max (since the graph opens down) is (4,36)
axis of symmetry is the x coordinate
max is (4,36)
axis of symmetrry is x=4