Problem K. 312. (November 2011)
K. 312. The vertices of a trapezium ABCD lying in the first quadrant of the coordinate plane are A(a;0); B(8;b); C(3;b); D(0;0), where a and b are integers. Given that the area of the trapezium is 121, find the missing coordinates.
(6 pont)
Deadline expired on December 12, 2011.
Sorry, the solution is available only in Hungarian. Google translation
Megoldás. A trapéz \(\displaystyle AD\) és \(\displaystyle BC\) oldalai párhuzamosak az \(\displaystyle x\)-tengellyel, \(\displaystyle AD\) hossza \(\displaystyle a\), \(\displaystyle BC\) hossza 5, a trapéz magassága pedig \(\displaystyle b\). A trapéz területe: \(\displaystyle \frac{(a+5)\cdot b}{2}=121\), azaz \(\displaystyle (a+5)\cdot b = 2\cdot 11^2\). Tudjuk, hogy \(\displaystyle a>0\), \(\displaystyle b>0\).
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Statistics:
209 students sent a solution. 6 points: 67 students. 5 points: 10 students. 4 points: 26 students. 3 points: 5 students. 2 points: 26 students. 1 point: 49 students. 0 point: 20 students. Unfair, not evaluated: 6 solutionss.
Problems in Mathematics of KöMaL, November 2011