Given 2 numbers which is greater lcm or gcm

To find the Least Common Multiple you first have to write down multiples of each number until one same multiple occurs in both lists. Once you find that multiple you can circle it to use it in your answer.

To find the greatest common factor you just have you list all the factors of that number and the other's too. Then you circle the largest factor that occurs in both lists.

Two angles are supplementary if their sum is a straight angle, which means that the sum of their measures is equal to 180°.

Therefore if you have ∡1 and ∡2 that are supplementary, it means that that measure of ∡1 plus the measure of ∡2 is equal to 180°, or M∡1+M∡2=180°;

Similarly, the measure of ∡2 plus the measure of ∡3 is equal to 180°, or M∡2+M∡3=180°

Since they are equal to the same quantity (180°), they must be equal to each other: M∡1+M∡2=M∡2+M∡3

You can subtract the measure of ∡2 from both sides: 
M∡1+M∡2-M∡2=M∡2+M∡3-M∡2
which brings to:
M∡1=M∡3

If two angles have the same measure they are said congruent, therefore ∡1 is congruent to ∡3.