You use the Pythagorean theorem which is a^2+b^2=c^2
So....
.8^2+.6^2=c^2
.64+.36=c^2
1=c^2
1=c becaaue the square root of one is one
Distributive property, commutative property, and associative property (I believe. I tried my best but I’m not completely sure that I’m correct. Good luck!)
Answer:
DE is parallel to AB, ∠ACB =∠DCE. So from symmetry of triangle. Δ DCE and Δ ABC are symmetric
3/4 is the simplest form of 9/12