Measurement
UK Secondary (7-11)
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Area
Lesson

Let's review the rules for areas of quadrilaterals, triangles and circles that we have covered so far.

Areas
Rectangle

 

$\text{Area of a Rectangle }=\text{length }\times\text{width }$Area of a Rectangle =length ×width

$A=L\times W$A=L×W

Square

$\text{Area of a Square}=side\times side$Area of a Square=side×side

$A=S\times S$A=S×S

$A=S^2$A=S2

Triangle

$\text{Area of a triangle }=\text{half of the area of the rectangle with base and height the same as triangle }$Area of a triangle =half of the area of the rectangle with base and height the same as triangle

$\text{Area of a triangle }=\frac{1}{2}\times\text{base }\times\text{height }$Area of a triangle =12×base ×height

$A=\frac{1}{2}bh$A=12bh

Parallelogram

$\text{Area of a Parallelogram }=\text{Base }\times\text{Height }$Area of a Parallelogram =Base ×Height

$A=b\times h$A=b×h

Trapezium

$\text{Area of a Trapezium}=\frac{1}{2}\times\left(\text{Base 1 }+\text{Base 2 }\right)\times\text{Height }$Area of a Trapezium=12×(Base 1 +Base 2 )×Height

$A=\frac{1}{2}\times\left(a+b\right)\times h$A=12×(a+b)×h

Kite

$\text{Area of a Kite}=\frac{1}{2}\times\text{diagonal 1}\times\text{diagonal 2}$Area of a Kite=12×diagonal 1×diagonal 2

$A=\frac{1}{2}\times x\times y$A=12×x×y

Rhombus

$\text{Area of a Rhombus }=\frac{1}{2}\times\text{diagonal 1}\times\text{diagonal 2}$Area of a Rhombus =12×diagonal 1×diagonal 2

$A=\frac{1}{2}\times x\times y$A=12×x×y

Circle

$\text{Area of a circle}=\pi r^2$Area of a circle=πr2

 

Worked Examples

QUESTION 1

Find the area of the rectangle shown.

QUESTION 2

Find the area of the parallelogram shown.

QUESTION 3

Find the shaded area shown in the figure.

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