# Math

posted by .

write an equation which must be true if the line from p(x,y) to a(25,0) is perpendicular to the line from P(x,y) to the center of the circle x^2+y^2=400

• Math -

I will make the assumption that P is on the circle
then if the centre is the origin , called O
then slope PO = -1/slope PA

y/x = -1/(y/(x-25) )
y/x = (25-x)/y

y^2 = 25x - x^2
but y^2 = 400 - x^2

400-x^2 = 25x - x^2
25x = 400
x = 16

## Similar Questions

1. ### Math

Write your answer in standard form. Show all your work if you want to be eligible for partial credit. Write the equation of a line perpendicular to the line y = (2/3)x - 7 and passing through the point (4,-2). The slope of the line …
2. ### Math 10

1 more question.... how would I make this equation perpendicular?
3. ### Geometry

Prove that the tangents to a circle at the endpoints of a diameter are parallel. State what is given, what is to be proved, and your plan of proof. Then write a two-column proof. Hint draw a DIAGRAM with the points labeled. Can some …
4. ### Writing this equation

how do I write the equation of a line perpendicular to the line 6x – 3y=10 and containing the point (-6, 2). The line you are given can have its equation rewritten im y = mx + b as: y = 2x - 10/3 That tells you that is slope is m …
5. ### Math (Pre Cal)

Hi, I am studying for a precalculus quiz and I do not understand this hw problem: "The tangent line to a circle may be defined as the point that intersects a circle in a single point... If the equation of the circle is x^2+y^2=r^2 …
6. ### Math

write an equation which must be true if the line from p(x,y) to a(25,0) is perpendicular to the line from P(x,y) to the center of the circle x^2+y^2=400