How to use the Consecutive Interior Angles Theorem? The interior angle sum of a triangle is 180 degrees. This is called the exterior angle property of a triangle. If ∠H = 60°, ∠E = 120° since those … Exterior angle properties . The measure of each interior angle of an equiangular n-gon is. The following figures give the some examples of co-interior angles. The sum of the measures of the interior angles of a polygon with n sides is (n – 2)180.. The exterior angle d is greater than angle a, or angle b. The side opposite to the largest angle of a triangle is the largest side. The measurements of the three interior angles are given. Properties of Angles. Any exterior angle of the triangle is equal to the sum of its interior opposite angles. Co-Exterior Angles: Exterior angles on the same side of the transversal. Two angles are said to be Co-exterior angles if they are exterior angles and lies on same side of the transversal. NCERT Class 9 Maths Lab Manual – Verify Exterior Angle Property of a Triangle OBJECTIVE To verify exterior angle property of a triangle. It is given that ∠H = 60°. Triangles can be classified in 2 major ways: Classification according to internal angles Types of triangles. The exterior angle of a triangle is equal to the sum of its interior opposite angles. Linear Pair of Angles The exterior angle d equals the angles a plus b. ... As Shown below, there are also two pairs of alternate interior angles and two pairs of alternate exterior angles. Notice how the interior angles are in between the two parallel lines and the exterior angles are to the outside. Theory For straight line refer to Activity […] Well, transversal is one of the main connecting links between any two lines (or parallel lines). Exterior Angles of a Triangle Worksheet 1 - This angle worksheet features 12 different triangles, all with one clearly identified exterior angle, represented by x.. So in the above figure ( ∠1 ∠8 ) , ( ∠2, ∠7 ) are Co-exterior angles. Exterior angles lie outside the parallel lines. Scroll down the page for more examples and solutions. We can use our knowledge of parallel lines to prove (deductively) this theorem. If you count one exterior angle at each vertex, the sum of the measures of the exterior angles of a polygon is always 360°. Materials Required Cardboard sheet Adhesive Glazed papers White chart paper Geometry box Tracing paper Cutter Prerequisite Knowledge Straight angle Exterior angle property of a triangle. When exterior alternate angles are equal, the lines are parallel. Simply add the two non-adjacent angles, and you have found the measure of the exterior angle. Properties of Angles and Straight Lines 1. The Consecutive Interior Angles Theorem states that if two parallel lines are cut by a transversal, then each pair of alternate interior angles is congruent. When two straight lines cross, vertically opposite angles are equal. Grades K-8 Worksheets. The total angle at a point is 360 ° w +x+y+z=3600 2. Hence the lines p and q are parallel. We can verify this using other angles. We can see that ∠B and ∠H are exterior alternate angles. So in the below figure ( ∠4, ∠5) , ( ∠3, ∠6) are Co-interior angles or consecutive angles or allied interior angles. The total angle on a straight line is 180 ° In the diagram, x+y+z=1800 3. - Corresponding angles - Alternate angles - Co-interior angles (supplementary) Angle sum of triangles . An exterior angle is the angle formed on the outside of the triangle. ... FOM 11 2.3 Angle Properties In Triangles The sum of the angles in a triangle is 180 °°°°.