Law of Sines Calculator

Law of Sines is evaluated from Side a, Angle A and Side b. The calculation reports Side a, Side b and Side c.

Results

Thanks — we’ve logged this for review.

About the Law of Sines Calculator

### Why Use the Law of Sines Calculator Calculator?
The Law of Sines Calculator is a valuable tool for solving problems involving oblique triangles, where not all sides and angles are known. This calculator is particularly useful in situations where two angles and one side, or two sides and one angle, are given. By using the Law of Sines formula, the calculator can determine the lengths of all sides and the measures of all angles in the triangle. This is especially useful in real-world applications such as navigation, surveying, and engineering, where precise calculations are critical. For example, a pilot may use the Law of Sines Calculator to determine the distance to a destination, given the angle of elevation and the distance to a known landmark. Similarly, a surveyor may use the calculator to determine the length of a side of a triangle, given the measures of two angles and the length of another side.

### History of the Law of Sines Calculator
The Law of Sines has its roots in ancient Greek mathematics, where it was first described by the astronomer and mathematician Hipparchus of Rhodes in the 2nd century BCE. However, it was not until the 16th century that the formula was fully developed and widely accepted. The German mathematician Regiomontanus is credited with popularizing the Law of Sines in his book "De triangulis omnimodis" in 1464. The formula was later refined and expanded upon by other mathematicians, including François Viète and Leonhard Euler. Today, the Law of Sines is a fundamental concept in trigonometry and is widely used in many fields, including mathematics, physics, engineering, and navigation.

### The Science Behind the Calculations
The Law of Sines states that for any triangle with angles A, B, and C, and opposite sides a, b, and c, the following equation holds: a / sin(A) = b / sin(B) = c / sin(C). This equation can be used to solve for any unknown side or angle in the triangle, given sufficient information. The calculator uses this formula to determine the lengths of all sides and the measures of all angles in the triangle. The variables in the equation represent the following: a, b, and c are the lengths of the sides of the triangle, and A, B, and C are the measures of the angles in degrees. The sine function is used to relate the angles and sides of the triangle. By rearranging the equation and solving for the unknown variables, the calculator can determine the desired values.

### Real-Life Application and Examples
Suppose a navigator is trying to determine the distance to a lighthouse, given the angle of elevation to the top of the lighthouse and the distance to a known landmark. The navigator measures the angle of elevation to be 30 degrees and the distance to the landmark to be 10 miles. Using the Law of Sines Calculator, the navigator can enter the known values and solve for the distance to the lighthouse. For example, if the navigator enters the values side_a = 10, angle_A = 30, and side_b = 14, the calculator will output the values side_a = 10.000000, side_b = 14.000000, side_c = 12.727922, angle_A = 30.0000, angle_B = 45.0000, angle_C = 105.0000, and area = 42.4264. The navigator can then use the calculated distance to the lighthouse to determine the navigation bearing and distance to the destination. In this example, the calculated distance to the lighthouse is approximately 12.73 miles. The navigator can use this information to adjust the navigation course and ensure safe passage.

Formula & How It Works

The calculation applies the following relations exactly as recorded in the metadata:

a/sin(A) = b/sin(B) = c/sin(C)
b = a x sin(B)/sin(A)
C = 180 deg - A - B

Each output field is produced by substituting the supplied inputs into the relevant relation and then applying the declared rounding or text format.

Worked Examples

Example 1: AAS — Surveying Triangulation

Inputs

side_a: 450 angle_A: 52 angle_B: 73
Side a: 450. Side b: 546.10567. Side c: 467.783489. Angle A: 52 deg. Angle B: 73 deg. Angle C: 55 deg. Area: 100,652.3045 units^2

With Side a = 450, Angle A = 52 and Angle B = 73 as the stated inputs, the result is Side a = 450, Side b = 546.10567 and Side c = 467.783489. Each value corresponds to the declared output fields.

Example 2: ASA — Navigation — Coast Guard

Inputs

angle_A: 65 side_b: 12 angle_B: 75
Side a: 11.259346. Side b: 12. Side c: 7.985552. Angle A: 65 deg. Angle B: 75 deg. Angle C: 40 deg. Area: 43.4242 units^2

With Angle A = 65, Side b = 12 and Angle B = 75 as the stated inputs, the result is Side a = 11.259346, Side b = 12 and Side c = 7.985552. Each value corresponds to the declared output fields.

Example 3: SSA — Ambiguous Case

Inputs

side_a: 7 side_b: 10 angle_A: 35
Side a: 7. Side b: 10. Side c: 7. Angle A: 35 deg. Angle B: 0 deg. Angle C: 145 deg. Area: 20.0752 units^2

With Side a = 7, Angle A = 35 and Side b = 10 as the stated inputs, the result is Side a = 7, Side b = 10 and Side c = 7. Each value corresponds to the declared output fields.

Example 4: Area from Two Sides and Included Angle

Inputs

side_a: 8 side_b: 11 angle_C: 40
Side a: 8. Side b: 11. Side c: 0. Angle A: 0 deg. Angle B: 0 deg. Angle C: 40 deg. Area: 28.2827 units^2

With Side a = 8, Side b = 11 and Angle C = 40 as the stated inputs, the result is Side a = 8, Side b = 11 and Side c = 0. Each value corresponds to the declared output fields.

Common Use Cases

  • Solve triangle from two angles and one side
  • Find unknown side in an oblique triangle
  • Calculate navigation bearing and distance
  • Determine satellite positioning from angles