Know Your Quadrilaterals. Triangle Song by Rockin' the Standards. Types of angles. Properties of Similar Triangles. Plastic glasses, plastic bottles, plastic days (tyler hallett : tytronic) StudyJams. StudyJams. Triangles. Triangles. Triangles - Equilateral, Isosceles and Scalene. Equilateral, Isosceles and Scalene There are three special names given to triangles that tell how many sides (or angles) are equal. There can be 3, 2 or no equal sides/angles: What Type of Angle? Triangles can also have names that tell you what type of angle is inside: Combining the Names Sometimes a triangle will have two names, for example: Play With It ...
Try dragging the points around and make different triangles: You might also like to play with the Interactive Triangle. Perimeter The perimeter is the distance around the edge of the triangle: just add up the three sides: Area The formula works for all triangles. Note: another way of writing the formula is bh/2 Example: What is the area of this triangle? (Note: 12 is the height, not the length of the left-hand side) Height = h = 12 Base = b = 20 Area = ½ × b × h = ½ × 20 × 12 = 120 The base can be any side, Just be sure the "height" is measured at right angles to the "base":