Here you can use the transitive property that if a=b and b=c the a=c
so just like that if cos A= cos B the A=B because after the putting the values of a and b in co u get the equal answer the it means that a and b are the numbers
1 1 1
The Brainliest Answer!
In traingle ABC,
As both angle A and angle B are acute, only angle C can be 90 degree (since all calculations in trigonometry are done with a right angled triangle.
Given, cos A = cos B
or, AC/AB  = CB/AB
or, AC = CB
Angle A = Angle B(Proved)
3 4 3