SOLUTION: A 1.8 meters tall person walks across the path of the javelin. He is 58 meters away from where the javelin was launched. Will he be hit by the javelin? Justify your answer. The

Algebra ->  Quadratic Equations and Parabolas -> SOLUTION: A 1.8 meters tall person walks across the path of the javelin. He is 58 meters away from where the javelin was launched. Will he be hit by the javelin? Justify your answer. The       Log On


   

Question 993876: A 1.8 meters tall person walks across the path of the javelin. He is 58 meters away from where the javelin was launched. Will he be hit by the javelin? Justify your answer.
The quadratic equation i'm given is: +y=-%282%2F75%29x%5E2%2B%2847%2F30%29x%2B2+
Do I replace 'x' with 58 and solve for y? so i know the height of the javelin at x=58 or 58 meters away to see if the javelin hit the person?
Like,
+y=-%282%2F75%29%2858%29%5E2%2B%2847%2F30%29%2858%29%2B2+
+y=-%282%2F75%29%283364%29%2B%2847%2F30%29%2858%29%2B2+
+y=-%286728%2F75%29%2B%2847%2F15%29%2829%29%2B2+
+y=-%286728%2F75%29%2B%281363%2F15%29%2B2+
+y=-%286728%2F75%29%2B%286825%2F75%29%2B2+
+y=-%286728%2F75%29%2B%286825%2F75%29%2B%28150%2F75%29+
+y=+%28247%2F75%29+
y ≈ 3.29m
Hence the javelin does not hit the person that is 1.8 meters tall.
Is this how i 'justify'?
Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
A 1.8 meters tall person walks across the path of the javelin. He is 58 meters away from where the javelin was launched. Will he be hit by the javelin? Justify your answer.
The quadratic equation i'm given is: +y=-%282%2F75%29x%5E2%2B%2847%2F30%29x%2B2+
Do I replace 'x' with 58 and solve for y? so i know the height of the javelin at x=58 or 58 meters away to see if the javelin hit the person?
Like,
+y=-%282%2F75%29%2858%29%5E2%2B%2847%2F30%29%2858%29%2B2+
+y=-%282%2F75%29%283364%29%2B%2847%2F30%29%2858%29%2B2+
+y=-%286728%2F75%29%2B%2847%2F15%29%2829%29%2B2+
+y=-%286728%2F75%29%2B%281363%2F15%29%2B2+
+y=-%286728%2F75%29%2B%286825%2F75%29%2B2+
+y=-%286728%2F75%29%2B%286825%2F75%29%2B%28150%2F75%29+
+y=+%28247%2F75%29+
y ≈ 3.29m
Hence the javelin does not hit the person that is 1.8 meters tall.
Is this how i 'justify'?
-----------------
y gives the height of the javelin for the given x, so that justifies your answer.
+y=-%286728%2F75%29%2B%286825%2F75%29%2B2+ should be
+y=-%286728%2F75%29%2B%286815%2F75%29%2B2+
+y=+%28237%2F75%29+
y =~3.16 meters
but that doesn't change the Yes or No answer.