To solve the inequality 3/10 is greater than or equal to k - 3/5, we must first set it up. Since 3/10 is greater than or equal to something, we will have a greater than or equal to symbol, with the 'mouth' pointing towards 3/10. Setting this up we get:
3/10 ≥ k - 3/5
Now we want to get k by itself on one side. We can do this by adding 3/5 to each side.
3/10 + 3/5 ≥ k
Simplify
9/10 ≥ k
C = 84 degrees
A = 2B
C = A + 20
A + B + C = 180
A = 2B
A/2 = B
A + (A/2) + (A+20) = 180
multiply each side by 2
2A + A + 2A + 40 = 360
combine like terms
5A + 40 = 360
subtract 40 from both sides
5A = 320
divide both sides by 5
A = 64
C = A + 20
C = 64 + 20
C = 84
