- 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
Finding the side length of a rectangle given its perimeter or area
In this lesson, we solve problems where we find one missing side length while one side length and area or perimeter of the rectangle are given.
Determine the value of 'L'.
Perimeter = 22 cm
Solution
Step 1:
Perimeter of a rectangle = 2(l + w); l = length = L; w = width = 6
Step 2:
Perimeter of given rectangle = 2(L + 6) = 22 cm
L + 6 = $\frac{22}{2}$ = 11;
So missing length L = 11 – 6 = 5 cm
Determine the value of 'L'.
Perimeter = 20 cm
Solution
Step 1:
Perimeter of a rectangle = 2(l + w); l = length = L; w = width = 7
Step 2:
Perimeter of given rectangle = 2(L + 7) = 20 cm
L + 7 = $\frac{20}{2}$ = 10;
So missing length L = 10 – 7 = 3 cm
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