Im literally so stressed right now. :

Tangent is a trigonometric ratio concerning itself with opposite and adjacent. We can set up a ratio saying that:


To solve for DE, we need to isolate it by multiplying by DE on both sides and then dividing by tan(22) to isolate it. We end up with:


Now, we can just plug it into a calculator and solve to get:


So your answer is DE ≈ 29.7 units. Hopefully, this made sense, and don't stress! You can ask me any further questions you have by DMs. Also, remember SOHCAHTOA for trig functions. SOH (sine opp hyp), CAH (cosine adj hyp) and TOA (tangent opp adj). It's a really helpful mnemonic.