The question asks to determine the temperature of the windows in a room with an air temperature of 15°C and 75% relative humidity. --- ### Given: - Room temperature, \( T_{air} = 15^\circ C \) - Relative humidity, \( RH = 75\% \) --- ### Step 1: Find the saturation vapor pressure at 15°C Using standard tables or approximation formulas, the saturation vapor pressure (\( P_{sat} \)) at 15°C is approximately **17.05 hPa**. ### Step 2: Calculate the actual vapor pressure \[ P_{v} = RH \times P_{sat} = .75 \times 17.05 \approx 12.79 \text{ hPa} \] ### Step 3: Find the dew point temperature The dew point is the temperature at which the vapor pressure equals the saturation vapor pressure. Using vapor pressure tables or approximation formulas, a vapor pressure of **12.79 hPa** corresponds approximately to a dew point of **12.7°C**. --- ### **Correct option:** **12.7°C**