A triangle contains angles measuring 25° and 75°. How many degrees is the third angle?

80 degrees

Step-by-step explanation:

A triangle has 180 degrees.

25+75=100

180-100= 80

That means the other angle must equal 80 degrees

hope it you

step-by-step explanation:

sin(7pi/6 - pi/3)  

= sin(7pi/6 - 2pi/6)  

= sin(5pi/6)  

= sin(pi - pi/6)  

= sin(pi/6)  

= 1/2  

sin 7pi/6 - sin pi/3  

= sin (pi + pi/6) - sin pi/3  

= -sin pi/6 - sin pi/3  

= -1/2 - sqrt(3)/2  

= -(1+sqrt(3))2