Analytic geometry - finding point by intersect lin

posted by .

I have a triangle ABC. The slope of AB is -1/ab, the slope of AC is -1/ac, and the slope of BC is -1/ac. My question is, I have 3 lines: Altitude from A to BC, altitude from B to AC, and altitude from C to AB. I know their slope because it is just -1/slope. But I want to know the coordinates of where they intersect. Could someone help me? thanks

  • Analytic geometry - finding point by intersect lin -

    The details get a bit messy, but you can place A=(0,0) B=(h,k) C=(m,n)

    Then the altitude from B to AC is
    y-k = -h/k (x-h)

    The altitude from C to AB is
    y-n = -m/n (x-m)

    solve for x and y.

    Trilinear coordinates are much cleaner, but less well known.

  • Analytic geometry - finding point by intersect lin -

    thanks a bunch

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. MATH!

    What type of lines have a slope of zero? Write the equation of a line with the slope of -2 which contains the point (3,6) The x-axis has 0 slope. What about any other line with 0 slope?
  2. Calculus

    How do you find Altitude and slope slope is the derivative of a function: for ex. if you have f(x)=x^2 + x, at point (1,2) f'(x)=2x+1 your slope is 2(1) + 1 = 3 =m to find the equation is y-y1=m(x-x1) so you have: y-2=3(x-1) gives …
  3. math, help

    can someone show me how to do this one i have plenty of them so can you show me step by step when someone gets a chance. Thank you. Solve the system by graphing x+y=3 x+y=-1 What I would do is to put the equations in slope intercept …
  4. Math /Algebra

    I was challenged with this question: Explain why the formula for determining slope using the coordinated of two points does not apply to vertical lines. This was my answer: The formula for determining a slope using two points does …
  5. math

    triangle ABC has vertices A(3,4), B(4,-3) and C(-4,-1). a. draw a sketch of the triangle b. draw the altitude from vertex A c. find the slope of side BC which is =-1/4 d. find the slope of the altitude from A which is 4 e. find the …
  6. Geometry

    In triangle ABC, A = (5, 9), B = (3, 1), and C = (11, 3). Write the equation of the altitude from A to BC. Use point-slope form ... y - y1 = m(x - x1).
  7. Geometry

    Triangle ΔABC has vertices A(2,5), B(8,1) and C(-2,-1) and is a right triangle. If the slope of AB is -2/3 and the slope of AC is 3/2, are the lines parallel, perpendicular or neither?
  8. math

    Triangle ΔABC has vertices A(2,5), B(8,1) and C(-2,-1) and is a right triangle. If the slope of AB is -2/3 and the slope of AC is 3/2, are the lines parallel, perpendicular or neither?
  9. math

    Which statement is true? A. All vertical lines have a slope of zero. B. All vertical lines have a slope positive slope. C. All vertical lines have a negative slope. D. All vertical lines have a undefined slope. WHY?
  10. Geometry

    I have two questions about finding the slope. 1. If a staircase has 8 inches of rise for every 12 inches of tread, what is the slope of the staircase?

More Similar Questions