Question

how to find interior angles of a triangle

Answer 1

1. The sum of the internal angles equals 180º ...A + B + C = 180º 2. The 'sine rule' ...3. The 'cosine rule' ...       a² = b² + c² - 2bc cosA    or       b² = a² + c² - 2ac cosB    or       c² = b² + a² - 2ba cosCWe will now use an example to show how these rules are applied to solve a triangle when two angles and one side length are given. Example: Solve this triangle for the unknown internal angle and sides:Step 1: Calculate the unknown angle. The sum of the internal angles equals 180º ...        A + B + C = 180ºso        C = 180º - (A+B)            =  180º - (30º+70º)           =  180º - 100º           =  80ºStep 2: Use the sine rule to find one unknown side. NOTE: The sine rule is easier to use than the cosine rule.To find side 'c' with the sine rule:               Step 3: Use the sine rule again to find the other unknown side. To find side 'a' with the sine rule: 

Answer 2

Sum of all the angles must be 180 now give eqnlet the angles in the triangle are I ratio of 1:2:3 then let the number be x then 1x+2x+3x=180 solve the equation to get answers