Given a rhombus ABCD. BD is its diagonal. BD = AD = 7 cm. Calculate the angles of the rhombus and its perimeter.

All sides of the rhombus are equal to each other, i.e. its perimeter is P = 4AD, P = 4 * 7 cm = 28 cm.

Diagonal BD divides rhombus ABCD into two equal triangles.

Consider a triangle ABD. It is equilateral, because by the condition BD = AD, and all sides of the rhombus are equal, then BD = AD = AB. Thus, all the angles of the triangle are equal to each other and are 180 ° / 3 = 60 °.

The opposite angles of the diamond BAD and DCB are equal to 60 °. The angles ADC and ABC are also equal to each other and amount to 2 * 60 ° = 120 °.

Answer: the angles of the rhombus are 60 °, 120 °, 60 ° and 120 °, P = 28 cm.