The Learning Point‎ > ‎Mathematics‎ > ‎Rhombus‎ > ‎

### Area of Rhombus of side 21 and Geometric properties like symmetry,perimeter of rhombus,diagonals of rhombus Area of a rhombus with side 21 units and base angle 30 degrees = side x side x sine of baseAngle = 21 x 21 x 0.5 = 220.5 square units Perimeter of a rhombus with side 21 units = 4 * side = 4 * 21 = 84 units Length of the two Diagonals of a rhombus with side 21 units = 2 * length of side * sin(BaseAngle/2.0) and 2 * length of side *cos(BaseAngle/2.0) = 2 * 21 * sine of 15.0 degrees and 2 * 21 * cosine of 15.0 degrees = 10.87 and 40.57 units Height of the Rhombus = Area of Rhombus / (length of side) = 10.5 units The order of symmetry of a rhombus is 2 (number of times the shape co-incides with itself during a 360 degree rotation). The symmetry group is dihedral. And it is isotoxal or edge-transitive in nature, though these are concepts and details which some of you might encounter later. The number of axes of symmetry of a rhombus is 2: the two diagonals In general, there are multiple formulas to compute the area of rhombus. Depending on information available you may use either of them. Area of a rhombus = (square of side) x sine(base Angle) = product of diagonals/2 = base x height To understand more about the geometric features and properties of a rhombus, formulas related to mensuration etc. you might find it useful to read the properties of a Rhombus tutorial over here. Many of these concepts are a part of the Grade 9 and 10 Mathematics syllabus of the UK GCSE curriculum, Common Core Standards in the US, ICSE/CBSE syllabus in India. Many of these concepts are a part of the Grade 9 and 10 Mathematics syllabus of the UK GCSE curriculum, Common Core Standards in the US, ICSE/CBSE/SSC syllabus in Indian high schools. You may check out our free and printable worksheets for Common Core and GCSE. Geometric Properties of a rhombus of side 16 units. Geometric Properties of a rhombus of side 17 units. Geometric Properties of a rhombus of side 18 units. Geometric Properties of a rhombus of side 19 units. Geometric Properties of a rhombus of side 20 units. Geometric Properties of a rhombus of side 21 units. Geometric Properties of a rhombus of side 22 units. Geometric Properties of a rhombus of side 23 units. Geometric Properties of a rhombus of side 24 units. Geometric Properties of a rhombus of side 25 units. Geometric Properties of a rhombus of side 26 units.