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.
The two angles opposite the two congruent sides of an isosceles triangle. The diagram shows an isosceles triangle with congruent sides line AB and line AC, and Base line BC. The congruent base angles, â B and â C, are marked in red. The angle opposite the base, â A, is called the vertex angle.