MathDB
Rectangle in a Triangle

Source:

June 8, 2009
geometryrectangleperimeter

Problem Statement

In right triangle ABC ABC, BC \equal{} 5, AC \equal{} 12, and AM \equal{} x; MNAC \overline{MN} \perp \overline{AC}, NPBC \overline{NP} \perp \overline{BC}; N N is on AB AB. If y \equal{} MN \plus{} NP, one-half the perimeter of rectangle MCPN MCPN, then: [asy]defaultpen(linewidth(.8pt)); unitsize(2cm); pair A = origin; pair M = (1,0); pair C = (2,0); pair P = (2,0.5); pair B = (2,1); pair Q = (1,0.5);
draw(A--B--C--cycle); draw(M--Q--P);
label("AA",A,SW); label("MM",M,S); label("CC",C,SE); label("PP",P,E); label("BB",B,NE); label("NN",Q,NW);[/asy] (A)\ y \equal{} \frac {1}{2}(5 \plus{} 12) \qquad (B)\ y \equal{} \frac {5x}{12} \plus{} \frac {12}{5}\qquad (C)\ y \equal{} \frac {144 \minus{} 7x}{12}\qquad (D)\ y \equal{} 12\qquad \qquad \,\, (E)\ y \equal{} \frac {5x}{12} \plus{} 6