the length of the floor clearance is 2.8 m
Step-by-step explanationas we have 2 similar triangles ( ABC and AED) we can set a proportion
Step 1
a)let

so
for triangle ABC ( divide the given measure by 100 to obtain meters)

and
for triangle AED
let

Step 2
as the ratio is the same, set the proportion

therefore, the length of the floor clearance is 2.8 m
I hope this helps you