Plane Trigonometry is a branch of mathematics that deals with the relationships between the angles and sides of triangles, particularly right triangles. It uses functions such as sine, cosine, and tangent to relate these angles and sides, allowing for the calculation of unknown lengths and angles in various applications. This field is essential in many areas, including engineering, physics, and architecture. By understanding the principles of plane trigonometry, one can solve problems involving distances, heights, and angles, making it a valuable tool in both theoretical and practical scenarios.