 ርዝመት ዘርጋ: ኤል, በጸደይ, L≈n1√ (πD2) & sup2 ለማድረግ ስራ ላይ የሚውለው ባዶ ርዝመት; + ረጥ & sup2;.
8. ballaariyo oo dhererkiisu: L, dhererka maran ee loo isticmaalo in laga sameeyo guga, L≈n1√ (πD2) & sup2, + t & sup2;.