Problem: In right triangle ABC,BC=5,AC=12, and AM=x; MN⊥AC,NP⊥BC;N is on AB. If y=MN+NP, onehalf the perimeter of rectangle MCPN, then:
Answer Choices:
A. y=21​(5+12)
B. y=125x​+512​
C. y=12144−7x​
D. y=12
E. y=125x​+6
Solution:
By similar triangles MN/x=5/12, or MN=5x/12. Also, NP=MC=12−x.∴y=12−x+5x/12=(144−7x)/12.
