Píngxíng sìbiānxíng de liǎng zǔ duìbiān fēnbié xiāngděng.
Both pairs of opposite sides of a parallelogram are equal.
Tips
usage
In a right triangle the sides are named from one acute angle: the 对边 faces it, the 邻边 runs beside it, and the 斜边 is the hypotenuse. So 正弦 (sine) is the 对边 over the 斜边, and 正切 (tangent) the 对边 over the 邻边.
