MathDB
Subtracting Triangles

Source: 2017 AMC 8 #18

November 22, 2017

Problem Statement

In the non-convex quadrilateral ABCDABCD shown below, BCD\angle BCD is a right angle, AB=12AB=12, BC=4BC=4, CD=3CD=3, and AD=13AD=13. [asy]draw((0,0)--(2.4,3.6)--(0,5)--(12,0)--(0,0)); label("BB", (0, 0), SW); label("AA", (12, 0), ESE); label("CC", (2.4, 3.6), SE); label("DD", (0, 5), N);[/asy] What is the area of quadrilateral ABCDABCD? <spanclass=latexbold>(A)</span>12<spanclass=latexbold>(B)</span>24<spanclass=latexbold>(C)</span>26<spanclass=latexbold>(D)</span>30<spanclass=latexbold>(E)</span>36<span class='latex-bold'>(A) </span>12\qquad<span class='latex-bold'>(B) </span>24\qquad<span class='latex-bold'>(C) </span>26\qquad<span class='latex-bold'>(D) </span>30\qquad<span class='latex-bold'>(E) </span>36