<prompt> Bainisha usemi wa eneo la pembetatu QCA kulingana na p. Jibu lako linapaswa kurahisishwa iwezekanavyo. asyukubwa5cm;kalamu chaguomsingifontsize9;jozi o 0, 0; jozi q 0, 12; jozi b 12, 0;jozi a 2, 12; jozi t 2, 0; jozi c 0, 9;chora-2, 0--15, 0, Kishale;chora0, -2--0, 15, Kishale;choraq--a--b;choraa--t;choraa--c--b;leboQ0, 12, q, W;leboA2, 12, a, NE;leboB12, 0, b, S;leboO0, 0, o, SW;lebox, 15, 0, E;leboy, 0, 15, N;leboT2, 0, t, S 0.6 E;leboC0, p, c, W;asy  <response>: Kwa kuwa QA ni sawa na QC, tunaweza kutibu QC kama urefu wa pembetatu QCA na QA kama msingi. Eneo la triangle QCA ni frac12times QAtimes QCfrac12times2-0times12-p frac12times2times 12-p12-p. 