# Past Papers’ Solutions | Cambridge International Examinations (CIE) | AS & A level | Mathematics 9709 | Pure Mathematics 1 (P1-9709/01) | Year 2016 | May-Jun | (P1-9709/13) | Q#11

Question Triangle ABC has vertices at A(−2,−1), B(4,6) and C(6,−3). i. Show that triangle ABC is isosceles and find the exact area of this triangle. ii. The point D is the point on AB such that CD is perpendicular to AB. Calculate the x-coordinate of D. Solution i. An isosceles triangle is a triangle with (at least) two equal sides. […]