Area & Volume Flashcards
to do area and volume
Regular shapes are?
shapes that can be recognised e.g. squares, rectangles, triangles, circles..etc
When a shape is irregular what do we use to find the area?
its area is found using the COUNTING THE SQUARES method which is
(i) divide the irregular shape into regular shapes that you can recognize such as triangles, rectangles, circles, squares…
(ii) find the area of these individual shapes and add them up!
Area of square is what?
(side)2
Area of rectangle is what?
length x breadth
Area of triangle is what?
½ (base x height)
Area of a circle is what?
π (r^2)
Radius( half of the diameter) squared multiplied by pi
π= 22⁄7 or 3.14
Volume of a cube is what?
(side)^3
Volume of a cuboid is what?
(length x breadth x height)
Volume of a cylinder is what?
π x radius squared x height
volume of a sphere is what?
4/3 x π x radius^3
When a shape is irregular, its Volume can be found using two methods name them
(i) displacement can method
(ii) the measuring cylinder method
Describe displacement can method
A displacement can is filled with water up till its spout. An empty beaker is placed at the bottom of the spout
The irregular shaped object is gently lowered into the displacement can. As the water level rises the displaced water falls out of the spout and into the beaker.
This water is then poured into a measuring cylinder and the volume is recorded.
Therefore the volume of the displaced (removed) object equals what?
The volume of the irregular shape
Describe the measuring cylinder method
A measuring cylinder is filled with water to approximately half and the volume of the water, Vi recorded.
The irregular shaped object is slowly lowered into the measuring cylinder
After the object is lowered, the water level rises and the new volume VF is recoded.
All readings must be taken at the bottom of the meniscus.
vi is what
initial volume
