# What is isosceles spherical triangle?

## What is isosceles spherical triangle?

An isosceles spherical triangle has an angle A=B= 54° and side b = 82°. Isosceles triangle – An isosceles triangle is a triangle that has two sides of equal length. The above two triangle is similar as they have a common property of two sides being equal.

### Are there triangles in spherical geometry?

Since spherical geometry violates the parallel postulate, there exists no such triangle on the surface of a sphere. The sum of the angles of a triangle on a sphere is 180°(1 + 4f), where f is the fraction of the sphere’s surface that is enclosed by the triangle.

What is a spherical triangle in geometry?

A spherical triangle is a figure formed on the surface of a sphere by three great circular arcs intersecting pairwise in three vertices. The spherical triangle is the spherical analog of the planar triangle, and is sometimes called an Euler triangle (Harris and Stocker 1998).

Is a spherical triangle with two equal sides?

17. Two spherical triangles are symmetrically equal if; (a) Three sides of one are correspondingly equal to the three sides of the other (b) Two sides and the included angle of one are respectively equal to the two sides and included angle of the other.

## What is the formula of spherical triangle?

Theorem: The area of spherical triangle △ABC is A + B + C − π. This quantity, A + B + C − π is called the excess. It’s amazing that the area has such a nice formula, depending only on the angles of the triangle!

### Is a lune a spherical triangle?

Spherical triangles. If we intersect a lune Λα with angle α of a pencil with poles AZ, with a third geodesic, which does not belong to the same pencil, and that therefore intersects the sides of Λα at points B and C, we divide the lune Λα in two regions with vertices ABC and ZBC, called spherical triangles.

Who is the father of spherical trigonometry?

Nasīr al-Dīn al-Tūsī
In the 13th century, Nasīr al-Dīn al-Tūsī was the first to treat trigonometry as a mathematical discipline independent from astronomy, and he developed spherical trigonometry into its present form.

What is spherical triangle properties?

A spherical triangle is a triangle each of whose sides is a great circle . The three angles of a spherical triangle must together be more than 180° and less than 540° . 7. The greater side is opposite the greater angle , if tow sides are equal their opposite angles are equal .

## Who is Father of spherical trigonometry?

### What is a lune in spherical geometry?

In spherical geometry, a spherical lune (or biangle) is an area on a sphere bounded by two half great circles which meet at antipodal points. It is an example of a digon, {2}θ, with dihedral angle θ.