good luck. I recommend you try putting the results of your work into a parser, to check if everything's right.
cijgu is an undefined gismu. the rafsi of 'ci' is -cib-, and the rafsi of 'jganu' is -jga-. that makes it 'cibjga', but it still doesn't mean anything sensible — one doesn't use number rafsi in gismu to signify the count of the tertau gismu this way. instead you have to use the word 'cibjgatai' — "form of three angles", or triangle.
'nilbra' — x1 is the size of object x2 in dimension x3 on scale x4. (jvajvo definition, may not match with the one in the dictionary)
'nilcla' — x1 is the length of x2 on scale x3. (as above)
the first one is more general, but you may want to use the latter one if you want to abuse 'clani''s assumption of a default dimension.
'.a'y bi'i by.' would be the line between A and B.
'lo cibjgatai... pe .a'y jo'u by. jo'u cy.' — the triangle ABC (that is, "of A, B and C in sequence")
— mi'e la uakci mu'o