Answer:
A trick I did when it comes to multiplying by 10, is just add a 0 at the end of the number your multiplying. Try for yourself!
[ 1 ] Given
[ 2 ] Exterior Sides Opposite Rays
[ 3 ] Definition of Supplementary angles
[ 4 ] First substitution
[ 5 ] Subtraction Property of Equality
[ 6 ] Second Substitution
[ 7 ] If corrsp. equal, the lines ||
Answer:


Step-by-step explanation:
Required
Find m and n
Considering the given angle, we have:

This gives:

Make m ths subject


So, we have:


Considering the given angle again, we have:

This gives:

Make n the subject


So, we have:


As there are 81 tiles total, that makes your area 81. Being a square, that makes your area equation A=s^2. As you need a side, this makes your equation s=√A. Plugging in 81 as A, we get s=√81=9, so an edge has 9 tiles.