You may be asked to show that two circles are touching, and say whether they're touching internally or externally. To do this, you need to work out the radius and the centre of each circle. If the sum ...

Summary We prove the next generalization of the Steiner-Lehmus theorem: if two equal cevians intersect with each other on the angle bisector of the third triangle vertex, then the triangle is ...

Depicted above are two intersecting tangent lines and two tangent circles. The tangent lines intersect at an angle θ = 142.9505685722O. The smaller circle has an area of 400 square meters. Find the ...

Parallel lines are lines that never cross each other - they keep the same distance apart from each other. When two lines intersect, the opposite (X) angles are equal. On parallel lines, alternate (Z) ...