# Cosine

Cosine and sine theorem:

Calculate all missing values from triangle ABC.

c = 2.9 cm; β = 28°; γ = 14° α =? °; a =? cm; b =? cm

Calculate all missing values from triangle ABC.

c = 2.9 cm; β = 28°; γ = 14° α =? °; a =? cm; b =? cm

## Correct answer:

Tips for related online calculators

Do you want to convert length units?

Cosine rule uses trigonometric SAS triangle calculator.

See also our trigonometric triangle calculator.

Cosine rule uses trigonometric SAS triangle calculator.

See also our trigonometric triangle calculator.

### You need to know the following knowledge to solve this word math problem:

**algebra**- expression of a variable from the formula
**planimetrics**- triangle
- The Law of Cosines
- The Law of Sines
**goniometry and trigonometry**- sine
- cosine

### Units of physical quantities:

### Grade of the word problem:

We encourage you to watch this tutorial video on this math problem: video1

## Related math problems and questions:

- Cosine

Cosine and sine theorem: Calculate all missing values (sides and angles) of the triangle ABC. a = 20 cm; b = 15 cm; γ = 90°; c =? cm; α =? °; β =? ° - The right triangle

In the right triangle ABC with a right angle at C, we know the side lengths AC = 9 cm and BC = 7 cm. Calculate the length of the remaining side of the triangle and the size of all angles. - Right angle

In a right triangle ABC with a right angle at the apex C, we know the side length AB = 24 cm and the angle at the vertex B = 71°. Calculate the length of the legs of the triangle. - Right triangle trigonometrics

Calculate the size of the remaining sides and angles of a right triangle ABC if it is given: b = 10 cm; c = 20 cm; angle alpha = 60°, and the angle beta = 30° (use the Pythagorean theorem and functions sine, cosine, tangent, cotangent)

- Right triangle

Calculate the length of the remaining two sides and the angles in the rectangular triangle ABC if a = 10 cm, angle alpha = 18°40'. - Right triangle

Calculate the missing side b and interior angles, perimeter, and area of a right triangle if a=10 cm and hypotenuse c = 16 cm. - Triangle's centroid

In the triangle ABC the given lengths of its medians tc = 9, ta = 6. Let T be the intersection of the medians (triangle's centroid), and the point S is the center of the side BC. The magnitude of the CTS angle is 60°. Calculate the length of the BC side t