To solve this problem, we can use the Pythagorean theorem to find the length of the ceiling.
Let's call the length of the ceiling "l". Then, using the Pythagorean theorem, we have:
l^2 + 20^2 = 29^2
Simplifying this equation, we get:
l^2 = 29^2 - 20^2
l^2 = 441
l = sqrt(441)
l = 21 meters
Paula will need 21 meters of garland for the length of the ceiling.
(If you’re confused on how I got it please comment!)