The Battle of Fredericksburg was fought December 11â15, 1862, in and around Fredericksburg, Virginia, between General Robert E. Lee 's Confederate Army of Northern Virginia and the Union Army of the Potomac, commanded by Major General Ambrose Burnside.
In an isosceles triangle that has exactly two equal sides, the equal sides are called legs and the third side is called the base. The angle included by the legs is called the vertex angle and the angles that have the base as one of their sides are called the base angles.
Whether the isosceles triangle is acute, right or obtuse depends on the vertex angle. In Euclidean geometry, the base angles cannot be obtuse (greater than 90Â°) or right (equal to 90Â°) because their measures would sum to at least 180Â°, the total of all angles in any Euclidean triangle.