1. SQUARE All sides equal Opposite sides parallel All angles are right
Diagonals equal
Diagonals perpendicular bisectors of each other.

2. RHOMBUS All sides are equal Opposite sides parallel
Diagonals perpendicular bisectors of each other.
Opposite angles equal.
Sum of angles on same side is 180.

3. Find the area o f this square?
3 cm
3 cm

4. Area of one triangle =½×b×h =½×3×3 =9/2 =41/2 Square centimetre
3cm
3 cm
Area of one triangle =½×b×h
=½×3×3
=9/2
=41/2 Square centimetre

5. Area of this square = 4×area of one triangle
=4×4 ½
=18 square centimetres

6. Let ‘d’ be the lengths of diagonals.
Lengths of perpendicular sides of each isosceles right triangles =1/2 d
Area of one such triangles =1/2×1/2d×1/2d
=1/8d²
Area of the square =4×1/8d²
=1/2d²

7. The area of square is half the square of the diagonals.

8. Area of the rhombus=4×1/2×3×2 =12 square centimetres
2 cm
3 cm
Area of the rhombus=4×1/2×3×2
=12 square centimetres

9. The area of the rhombus is half the product of its diagonals

10. PROMBLEMS Compute the area of a square of diagonals 5 centimetres.
Draw a rhombus of area 28 square centimetres.