Question

PLEASE HELP!! WILL AWARD BRAINLIST TO WHOEVER HAS ALL THE CORRECT CALCULATIONS!

Answer 1

Law of cosine:

c² = a² +b² -2ab*cosC.

Because the triangle is equilateral a=b=c=x,

and we can write,

x²=x² +x² -2xx*cosC

x² =2x² -2x²* cos C

-x² = -2x²*cos C

cos C= 1/2,

so m∠C=60⁰.

Because all sides are equal, and across of the equal sides should be equal angles, all angles will be also equal and = 60⁰.

Answer 2

Using the law of cosines, set up the equation and solve:

s^2 = s^2 + s^2 - 2 (s) (s) (cos x)

s^2 = 2s^2 - 2s^2 cos x

-s^2 = - 2s^2 cos x

0.5 = cos x

60 = x

This shows that all angles in an equilateral triangle must equal 60 degrees.

Hope this helps!