If you don't have a carpenter's square, you can still ensure that you are scribing a right angle by using the principles of mathematics. The formula for a right triangle is this: a^2 + b^2 = c^2, where "^2" means "squared." Consequently, if you measure the two sides of your angle, you can use the "c" factor -- also known as the hypotenuse -- to make sure that your right angle is, indeed, square. So, you see: Paying attention in high school geometry class really can pay dividends in real life.
Things You'll Need
- Tape measure
Using a tape measure, measure 3 inches on one side of the angle you want to be at 90 degrees and make a mark with your pencil. Then measure 4 inches on the other side of the angle and make a mark.
Measure between the two marks and you should have 5 inches. If you don't have 5inches between the marks, move the sides of the angle closer together or further apart until the space between measures 5 inches.
Just remember that 3 + 4 = 5. (Or, in our equation, 3^2 + 4^2 = 5^2.) This will work for a right angle every time. If your project is large you can use three feet on one side and four feet on the other side (instead of inches).
How to Lay Out a 90-Degree Angle With Just a Measuring Tape
When laying out a floor, garden or other home improvement project, it's not always easy to make right angles. If your project...
How to Create a Wheelchair Ramp Using Right Angled Triangle Trigonometry
Wheelchair accessibility requires modifications to house and home. Steps and stairs pose a major obstacle to people confined to a wheelchair. Overcoming...
How to Calculate Angles in Carpentry
Building a roof or cutting stringers for a stairway requires finding angles, marking and cutting them correctly. In carpentry, you usually do...
How to Figure Out a 45-Degree Angle
If you need to figure out a 45-degree angle and you don't have a protractor handy, you can create a workaround. A...
How to Make a Perfect Right Angle on a Fence
If you are installing a fence to enclose a square area, you want the corners to form 90 degree angles. An effective...