WHAT IS A square + B square= C square mean??

Name the most appropriate metric unit for each measurement like the mass of cow

The figures below are made out of circles, semicircles, quarter circles, and a square. find the area and the perimeter of each figure and give your answers as a completely simplified exact value in terms of π (no approximations).

Atriangle has a side lengths of 18cm, 80 cm and 81cm. classify it as acute obtuse or right?