Which instrument is used to check right angles and levels, and can also be used for measuring?

• A. Engineers square
• B. Vernier caliper
• C. Combination square
• D. Scriber

Answer: (C)

A combination square is a versatile measuring tool because it blends a straightedge, a 90-degree head, and a bubble level into one instrument. This lets you do three things reliably: check right angles, verify level, and take measurements.

To check a right angle, you align the ruler with the edge of your work and use the head to form a perfect 90-degree corner; if the edge sits flush against the blade, the angle is true. For level, the bubble vial in the head shows level whenever the bubble sits centered between the marks, so you can confirm horizontal or vertical orientation. For measuring, you read the scale on the ruler to determine lengths, and the adjustable head lets you transfer measurements, mark depths, or align the tool to set a consistent height for scribing or cutting.

Other tools lack one or more of these functions: an engineers square checks only a right angle without a built-in level or depth measurement; a vernier caliper provides precise linear measurements but isn’t designed for checking angles or level; a scriber marks lines but doesn’t measure or verify angles or levels.