Geometry Homework: Finding the Ratio BP : PC in a Right Triangle with Midpoint M

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Homework Help Overview

The problem involves a right triangle ABC where A is the right angle, and AB equals AC. The midpoint M of side AC is given, and point P is located on side BC such that line AP is perpendicular to line BM. The task is to find the ratio BP : PC.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss various geometric properties and relationships within the triangle, including the use of parallel lines and mass points. Some express uncertainty in their approaches while others share findings and suggest methods for solving the problem.

Discussion Status

The discussion includes multiple perspectives on the problem, with some participants suggesting potential solutions while others are still exploring their reasoning. There is no explicit consensus on the final answer, but several lines of reasoning have been presented.

Contextual Notes

Participants reference visual aids and attachments to support their reasoning, indicating a reliance on geometric diagrams. There is mention of specific mathematical concepts like mass points, which may not be familiar to all participants.

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Homework Statement



Let ABC be a right angled triangle such that A=90, AB=AC and let M be the mid point of the side AC. Take the point P on the side BC so that AP is vertical to BM. Let H be the intersection of AP ad BM.

Find the ratio BP : PC.

Homework Equations



AB=AC
AM = MC

BP : PC = ?

See the problem here: http://4.bp.blogspot.com/_Qc1Z3hIcYO4/SgbXNoa555I/AAAAAAAABPM/ruupwSz5EoE/s1600-h/bp_pc.JPG.

The Attempt at a Solution



I drew parallel lines, and I found some interesting connections. I am very close to the answer, but I still cannot find it.

Please, see the attachment "parallel_lines.jpg".
 

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Mass points kill this problem in about 2 seconds. Assign mass 2 to points C and A, so point M has mass 4. Using the fact that BAM ~ BFA ~ AFM, you can find that BF/FM = 4, so point B has mass 1. Thus, BP/CP = [ C ]/[ B ] = 2:1 (where [ ] denotes mass).

If you don't know what mass points are, you should go learn about them immediately. (They're awesome.)
 
VKint said:
Mass points kill this problem in about 2 seconds. Assign mass 2 to points C and A, so point M has mass 4. Using the fact that BAM ~ BFA ~ AFM, you can find that BF/FM = 4, so point B has mass 1. Thus, BP/CP = [ C ]/[ B ] = 2:1 (where [ ] denotes mass).

If you don't know what mass points are, you should go learn about them immediately. (They're awesome.)

Great thanks for the awesome tip!
 

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