Friday, September 28, 2018

Geometry Problem 1390: Triangle, any point, perpendicular, sum of the squares, Tutoring

Geometry Problem. Post your solution in the comment box below.
Level: Mathematics Education, High School, Honors Geometry, College.

Details: Click on the figure below.

Geometry Problem 1390: Triangle, any point, perpendicular, sum of the squares, Tutoring.

3 comments:

  1. connect PA,PB,PC;
    e1^2-f^2=PF^2 - PE^2;
    d1^2-e^2=PE^2-PD^2;
    f1^2-d^2=PD^2-PF^2;
    add together, right side =0;
    so e1^2+d1^2+f1^2=e^2+d^2+f^2;

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  2. Let PD = x, PE = y & PF = z

    Using Pythagoras 6 times

    PA^2 = d^2 + x^2 = f1^2 + z^2 ....(1)
    PB^2 = e^2 + y^2 = d1^2 + x^2 ...(2)
    PC^2 = f^2 + z^2. = e1^2 + y^2 ...(3)

    Adding these 3 equations together the result follows

    Sumith Peiris
    Moratuwa
    Sri Lanka

    ReplyDelete
  3. Connect PA, PB, PC
    Apply Pythagoras theorem we have
    e^2-e1^2= PB^2-PC^2
    f^2-f1^2= PC^2-PA^2
    d^2-d1^2= PA^2-PB^2
    add these expressions side by side we have d^2+e^2+f^2= d1^2+e1^2+f1^2

    ReplyDelete