수식 29: StartFraction, "B" Subscript, 1 , Baseline minus "J" Subscript, 1 , Baseline Over "B" Subscript, 2 , Baseline minus "F" Subscript, 2 , Baseline , EndFraction equals StartFraction, "B" Subscript, 1 , Baseline minus "H" Subscript, 1 , Baseline Over "H" Subscript, 2 , Baseline minus "F" Subscript, 2 , Baseline , EndFractionB1−J1B2−F2=B1−H1H2−F2