- Perimeter and Area of Polygons
- Home
- Sides of polygons having the same perimeter
- Finding the missing length in a figure
- Perimeter of a piecewise rectangular figure
- Area of a rectangle involving fractions
- Distinguishing between the area and perimeter of a rectangle
- Areas of rectangles with the same perimeter
- Word problem involving the area of a square or a rectangle
- Finding the side length of a rectangle given its perimeter or area
- Area of a piecewise rectangular figure
- Area between two rectangles
- Finding the area of a right triangle on a grid
- Finding the area of a right triangle or its corresponding rectangle
- Area of a triangle
- Finding the area of a trapezoid on a grid by using triangles and rectangles
- Area involving rectangles and triangles
- Area of a parallelogram
- Area of a trapezoid
- Finding the perimeter or area of a rectangle in the coordinate plane
Perimeter of a piecewise rectangular figure
In this lesson, we find the perimeter of given piecewise rectangular figures.
We are given piecewise rectangular figures with some measurements while some other ones are missing. We first find these missing lengths. In these figures, it is assumed that all intersecting sides meet in right angles. It is noted that opposite sides of a rectangle are parallel and equal in length while calculating the missing lengths. We also split the given figure into two rectangles for same purpose.
Once the missing lengths are found, adding up the length along the outer boundary of the given figure gives the perimeter of the given figure.
Find the perimeter of the following figure. Notice that some length is not given. Assume that all intersecting sides meet at right angles.
Solution
Step 1:
Missing lengths 7 – 3 = 4 cm; 5 – 2 = 3 cm
Step 2:
Perimeter of given figure = 5 + 7 + 2 + 4 + 3 + 3 = 24 cm
Find the perimeter of the following figure. Notice that some length is not given. Assume that all intersecting sides meet at right angles.
Solution
Step 1:
Missing lengths 60 – 40 = 20 mm; 30 + 15 = 45 mm
Step 2:
Perimeter of given figure = 45 + 60 + 15 + 40 + 30 + 20 = 210 mm
Opposite sides of rectangles are of same length.
Now we can find the perimeter of the figure by adding all lengths.
