141. Solving a chemistry problem

Cis-1,2-dichloroethylene in vinylidene chloride was determined by gas chromatography using toluene as an internal standard, and the following data were obtained for the calibration graph:
Sx / St 0.72 0.90 1.08 1.28
w,% 0.5 1 1.5 2
Calculate the mass fraction (%) of cis-1,2-dichloroethylene in the test sample using the following data on the peaks of the analyte and standard substance (take k = 1)
Peak cis-1,2-dichlorethylene Base 14 Height 42
Toluene Peak Base 18 Height 45