How to Calculate Bicycle Ramp Angles

Extreme sports offer a chance to combine math and thrills.

Building a bicycle ramp offers you a chance at a thrilling ride. Most people jumping off of a bicycle ramp rarely stop to calculate their velocity. However, pausing to calculate the angles of a bicycle ramp can help you predict how far you will travel, depending upon your speed. You do not need to know all the details of a ramp to calculate the angles of the ramp. You know that the base angle is 90 degrees, so if you measure the height, length and run of the ramp, you can use those measurements to calculate the other two angles.

Things You'll Need

• Carpenter's Square
• Mathematics Calculator (with SIN function)

Instructions

Use Trigonometry

1. Measure the length of the surface of the ramp, the distance on the ground from the start of the ramp to the end of the ramp, and the height of the ramp.

2. Divide the height of the ramp by the length of the surface of the ramp (the run of the ramp) to calculate the SIN of the angle at the base of the ramp. For example, if the height of the ramp is three feet and the length of the surface is five feet, you would divide three by 5 for a result of 0.6. SIN, also written as Sine, is a mathematical measurement of an angle used for complex calculations and measurements, such as finding an angle when you only have measurements of two sides of a triangle. Fortunately, many calculators have a "SIN" button that can calculate this for you.

3. Input the value that you receive and press the inverse SIN button ("SIN -1") on the calculator. The result is the angle at the start of the ramp. Following the same example, you would enter "0.6" into the calculator and press the "SIN-1" button to get an angle of 36.87 degrees.

Use a Carpenter's Square

1. Use a carpenter's square (a triangle tool used by carpenters to measure the angle of an item) to measure the angle of the ramp. You will see how the carpenter's square measures angles by looking at the angle markings on its slanted edge.

2. Place the carpenter's square with one edge flat on the ground adjacent to the ramp. The slanted edge of the ramp should be rising in the opposite direction of the slanted edge of the carpenter's square.

3. Slide the carpenter's square forward until the vertical edge of the triangle is flush with the angle you want to measure.

4. Mark where the ramp intersects the carpenters square. The mark on the square will tell you the angle of the ramp.

5. Subtract that measurement from 180 to determine the remaining angle, if desired.

Tips & Warnings

• Once you know one angle, you can identify the other angle by subtracting the angle you have measured from 180. The other angle is the difference.

• Inversely, if you wish to find out how long your ramp must be to have a 30 degree angle (or any other angle) at the base, type 30 (or the desired measurement of the angle) into the calculator and press the "SIN" button. Divide the answer by the height that you want the ramp to be. Then, divide the number 1 by the results of the prior calculation to get the length the ramp should be.

References

• Easy Calculations: Angle and Side Calculations Online
• CSG Network: Right Triangle Side and Angle Calculator
• Math Warehouse: Inverse Sine, Cosine, and Tangent