AREA
1.1 Area of closed plane figures
Area of a rectangle = length x breadth
Area of a square = (length of a side)2
Area of a parallelogram = length of a side x perpendicular distance between that side and the side parallel to it
Area of a triangle = 1/2 x base x altitude
Area of a circle = 22/7 (radius)2
EXERCISE:-
1. Find the Area of the following closed plane figures.
  
when b = 10cm and h = 4cm when r = 4cm if w = 12cm, h = 24cm
when b = 3cm and h = 4 cm when r = 1/11cm if w = 18cm, h = 15cm
when b = 9cm and h = 15cm when r = 7/22cm if w = 7cm, h = 5cm
 
if a = 12cm b = 6cm and h = 8cm
if a = 4cm b = 15cm and h = 4cm
if a = 10cm b = 11cm and h = 18cm
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| PERIMETER
1.Perimeter of closed plane figures
1-The Perimeter of a rectangle of a length 'a' and breadth 'b' = 2(a+b)
2-The Perimeter of a square of side 'a' = 4a
3-The Perimeter (circumference) of a circle of radius 'a' = 2 x 22/7 x a
Exercise:-
A rope is drawn round a circular ground.
1. If the length of the rope is 220m, what is the radius of the ground.
2. If this rope drawn round a semi-circular ground, what is the length of the straight edge??
A track 7m wide consists of two concentric circles. The circumference of the inner circle is 440m. find,
1. the radius of the outer circle.
2. the circumference of the outer circle.
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