#area of rectangle

Area of Rectangle in C

Quadrilaterals are polygon of four sides and vertices. These can be of different shapes. How to calculate area of quadrilaterals of different shapes are explained here with examples.

The topic covers are

Area of a square Area of a rectangle Area of a parallelogram Area of a rhomboid Area of a quadrilateral Area of a trapezoid

How to calculate area of a square

            where, a is the sides of square.

Example: calculate the area of square whose sides each measuring  4cm. Solution : Area=4 x 4 = 16 cm2

How to calculate area of a rectanlge

          where, and are two sides of rectangle.

Example: calculate the area of rectangle whose sides measuring  4cm and 8 cm. Solution : Area=4 x 8 = 32 cm2

How to calculate area of a parallelogram

    where  is the base,   is the height, and area is multiply of both.

Example: Find the area of a parallelogram with a base of 18 centimeters and a height of 5 centimeters. Solution : Area=18 x 5 = 90 cm2

How to calculate area of a rhombus

Area of rhombus can be calculated using three different methods

1. the “base height” method

   where,  is the base,   is the altitude or height,

2. the diagonals method

  where, and are diagonals of rhombus.

3. using trigonometry

where, is the length of any side is any interior angle

How to calculate area of quadrilateral

 and  

Where, a,b,c,d=sides of quadrilateral θ1,θ2 are angles of quadrilateral

How to calculate area of trapezoid

  where, and are parallel base and is height.

Example: Find the area of a trapezoid with bases of 9 centimeters and 7 centimeters, and a height of 3 centimeters

Solution: Area= (9+7).3/2 = 24 cm2

Area of a rectangle

The formula for area of a rectangle is b*h (base times height)

In a rectangle the opposite sides are congruent so if you the measure of one side then you also know the measure of the opposite side.   

 Please watch the video to see each problem worked out

You Tube Area of a Rectangle

Here is a list of area formulas plane shapes

Problem 1. Find the area of a rectangle with a base of 10 units and a height of 8 units.

  Step 1. Plug the numbers into the formula b*h 

  8 * 10 =80 units squared

  Next, let’s look at one more challenging. 

  Problem 2. Find the base of a rectangle with an area of 100 units and a height of 5 units.

  Step 1. Write the formula for the area of a rectangle Area= b*h

  Step 2. Plug in what you know 100 = b * 5

  Step 3 Divide each side by 5   100/5= b/5  

  Step 4. 20 =b and b = the base of the rectangle

  Problem 3. Find the area of a rectangle with a diagonal of 15 units and a side of 9 units.

  Step 1. Plug in what you know A = b * 9

  Step 2. The diagonal divides the rectangle into a right triangle. You can use the Pythagorean Theorem to find the base. 

A = 9 c= 15 b=your unknown (see picture below)

      9^2+ b^2= 15^2 

81+ b^2=225

b^2=144  

b=√144 

b = 12

    Step 3. Use your area formula of a rectangle Area = b*h