I'm more than abit rusty and am lost!

I need to use the transitive property to solve this problem?

M<1+ M<2= 180 degrees

M<3+ M<2= 180 degrees

M<1=M<3

???

Any help would be much appreciated with detailed instructions explaining steps.

(< is suppose to be acute angle sign.. I dont know how to make one on here.)

Thanks so much