one angle of a triangle is 60 degree the other two angles are in the ratio 5:7 find the two angles
Answers
One angle of a triangle is 60 degree the other two angles are in ratio 5:7. The two angles are 50° and 70°.
Stepwise explanation is given below:
- Measure of one of the angle of a triangle = 60°.
- Other two angles are in the ratio 5:7
- Let the other two angles be 5x and 7x.
- So, we know the sum of the angles of a triangle is 180°.
then, 5x+7x+60° = 180°
12x+60° = 180°
12x = 180° - 60°
12x = 120°
x = 120/12
x = 10°
so, the measure of other two angles will found by putting the value x = 10 is :-
=5x = 5*10 = 50°
And, 7x = 7*10 = 70°
Given :
For a Triangle ,
One angle of triangle = 60°
The ratio of other two angles = 5 : 7
To Find :
The other two angles
Solution :
For A Triangle
The Sum of all three angles of Triangle = 180°
Let ∠ A , ∠B , ∠C are three angles of Triangle ABC
let ∠ A = 60°
And ∠ B = 5 x°
And ∠ C = 7 x°
∵ ∠ A + ∠B + ∠C = 180° ...........1
Put the value of ∠ A , ∠B , ∠C in eq 1
So, 60° + ∠B + ∠C = 180°
Or, ∠B + ∠C = 180° - 60°
Or, ∠B + ∠C = 120°
Or, 5 x° + 7 x° = 120°
Or, 12 x° = 120°
∴ x =
i.e x= 10°
So, The value of ∠ B = 5 x° = 5 × 10° = 50°
And The value of ∠ C = 7 x° = 7 × 10° = 70°