Which joint is a 45-degree joint often used in picture frames?

• A. Dovetail Joint
• B. Mitre Joint
• C. Tongue and Groove
• D. Screw Joint

Answer: (B)

The main idea here is how joints create clean, angled corners for picture frames. A mitre joint is formed by cutting the ends of the two frame pieces at 45-degree angles so they meet to form a neat 90-degree corner. This specific 45-degree cut is why it’s the go-to choice for frames—it hides end grain and gives a tidy, decorative edge.

Dovetail joints are interlocking and very strong, usually used in drawers and boxes, not for frame corners. Tongue and groove is about fitting a projection (tongue) into a groove along the length, common in panels or flooring, not for making a corner. A screw joint is just fastening pieces together with screws and doesn’t produce the characteristic mitered corner required for picture frames.