acute

In a right-angled triangle, the other two internal angles must always be acute angles.

(Chinese) 在直角三角形中，另外两个内角必须始终是锐角。

The architect used acute angles in the roof design to give the building a sharp, modern appearance.

(Chinese) 建筑师在屋顶设计中使用了锐角，使建筑呈现出犀利且现代的外观。