I’m pretty sure that it is the 3 or C option.
I think you would use the Pythagorean Theorem to solve this, as a square cut across diagonally creates two isocele triangles. Since the longest side is 20 m, this value would be imputed into c^2.
a^2 + b^2 = c^2
a^2 + a^2 = 20^2
2a^2 = 400
2a^2/2 = 400/2
a^2 = 200
a = 14.14
Thus, each sides of the playground are 14.14 meters long.
Tan(A) = Opp/Adj = CB / AC = 12/9 = 4/3
hope it helps
The slope is 0 and the equation is y = -2
Try this solution:
let the unknown two-digits number be 'xy'.
Then it is possible to write any two-digit number as 10x+y, where x - the tens digit and y - the unit digit.
Using the rule described above the phrase 'the tens digit of a number is twice the units digit' may be written as x=2y.
Using the same rule the phrase 'if the digits are reversed, the new number is 36 is less than the original number' may be written as (10x+y)-(10y+x)=36.
These two equations may be resolved as system of two equations:

Check: the original number is 84, the new number is 48; difference is 84-48=36.
answer: 84