If you are given the measurements of the base and height of a triangle you can use this formula.[br][img width=75,height=27]https://lh4.googleusercontent.com/iz0ac9oMg4zsmISZ2D6C2Af1h2KMROPiXyoQqhKshsiBw-U_GVBYoibWwtKpCAdhDnpnHEpAeeXcS6t7bozowYH-xYh1azSIdOsw-bl8vMTvSQGYxSTc2haxhYHjIMzGa1WqIuIV[/img][br]If you don't have those measurements and the triangle is on a graph you can solve it like this:[br]First you have to find the side lengths of the triangle. [br]You can find the side lengths of a triangle by finding the rise over run between two of the points. [br]From point A to B you have to go over 6 and down 1, so you would plug this number into the area formula of a triangle. [br][br]a=½*bh[br]a=½*(1)(6)[br]AB=3[br]Continue this process for the other two sides. [br]BC:[br]a=½*(4)(5)[br]BC=10[br][br]CA:[br]a=½*(1)(5)[br]CA=2.5[br][br]Next find the total area surrounding the triangle. In this example this area is represented by a blue box. [br]Using the formula that we learned in the previous example find the area of the square. [br]L*W[br]5*6=30[br][br]Now take the total area of the shape (30) and subtract the smaller areas from it. [br]30-2.5-10-3=14.5[br]This means that the area of the triangle is 14.5 units ^2.[br][br][br][br][br][br]