🔍 Key Concepts

• Use the dry bulb temperature of 90°F along the bottom horizontal axis of the psychrometric chart • Locate the 65% relative humidity curve among the curved lines sloping upward to the left • From the intersection of 90°F dry bulb and 65% RH, follow the slanted wet‑bulb temperature lines to read the wet‑bulb value

💭 Think About

• When you are at 90°F on the dry bulb axis and move up to meet the 65% RH curve, what family of lines passes through that intersection? • As you trace along that slanted line, which labeled wet‑bulb temperature does it most closely match, and how does that compare to the answer choices? • Is the wet‑bulb temperature expected to be closer to the dry bulb or much cooler when relative humidity is as high as 65%?

✅ Before You Answer

• Confirm you are on the correct 90°F mark along the dry bulb axis before moving upward • Verify you are using the 65% RH curve, not 60% or 70% • Double‑check which wet‑bulb temperature label the intersection actually lies on or nearest to before matching it to one of the choices