 Hello and welcome to the session. Let us understand the following problem today. In a triangle ABC angle C is equal to trisor angle B which is equal to trisor angle A plus B. Find the three angles. Now first we see that some of the three angles of a triangle is equal to 180 degree. Now this is the key idea to our question. Now let us write the solution. Here angle ABC are the angles of a triangle. So angle A plus angle B plus angle C is equal to 180 degree by the key idea. Now let angle A is equal to x degree, angle B is equal to y degree. Now it is given to us that angle C is equal to trisor angle B. Therefore angle C is equal to 3 into y degree. Also it is given to us that trisor angle B is equal to trisor angle A plus B. Therefore trisor angle B that is y degree is equal to trisor x degree plus y degree. Which implies 3 into y degree is equal to trisor x degree plus trisor y degree. Which implies trisor x degree minus y degree is equal to 0. This is our equation 1. Now here we know that angle A plus angle B plus angle C is equal to 180 degree. Since angle A plus angle B plus angle C is equal to 180 degree by angle some property of a triangle. Which implies x plus y plus 3y is equal to 180 degree. Which implies x degree plus 4y degree is equal to 180 degree. This is our equation 2. Now solving equation 1 and 2. And for that multiplying equation 2 by 2. Now first of all writing equation 1 as it is we get 2x degree minus y degree is equal to 0. Now multiplying equation 2 by 2 and then writing so we get twice of x degree plus 8y degree is equal to 360 degree. Now subtracting it and do not forget to change the signs while subtracting. This gets cancelled so we are left with minus y minus 8y is equal to minus 9y which is equal to minus 360 degree. Now here this minus and minus gets cancelled so y degree is equal to 360 degree by 9. Which implies y degree is equal to 40 degree. Now substituting y is equal to 40 degree in equation 1 we get we have equation 1 as 2x minus y is equal to 0. So it implies 2x degree minus 40 degree is equal to 0. Which implies 2x degree is equal to 40 degree. Which implies x degree is equal to 20 degree. Now we see that angle A is equal to x degree which is equal to 20 degree. Angle B is equal to y degree which is equal to 40 degree. And angle C is equal to twice of angle B which is equal to 3 multiplied by 40 degree which is equal to 120 degree. So the required answer is angle A is equal to 20 degree. Angle B is equal to 40 degree and angle C is equal to 120 degree. I hope you understood the problem bye and have a nice day.