What is the sum of the measures of the internal angles of a triangle is

We just started the introduction into circles and i have no idea how to do this.

Complete the solution of the equation. find the value of y when x equals to 28 x+3y=28

Sam is a waiter at a local restaurant where he earns wages of $5 per hour sam figures that he also eams about $3 in tips for each person he serves sam works 6 hours on a particular day. if n represents the number of people sam serves that day, which of the following functions could sam use to figure ehis total earings for the do o a. en) = 30 o b. en) = 5n+ 18