How to Find the Area of the Blue Rectangle? Step-by-Step Explanation
Puzzle Overview
The First rectangle has an area of 20 m².
The Third rectangle has an area of 25 m².
The middle rectangle (colored blue) has an unknown area we need to find.
The Length From Start of First Rectangle to End of Second rectangle is 7 meters.
The Length From Start of Second Rectangle to End of Third rectangle is 8 meters.
1. Find the Common Height
From the image known all three rectangles they share the same height.
Let’s first find the height using the information from the image
For the First rectangle:
Area = Length x Height , Given area = 20 m².
Now, from the figure:
-
-
Suppose the Length of the left rectangle is 4 meters.
-
Then the height will be
-
Height = Area / Width
- Height = 20 / 4 = 5 Meters
-
For the Third rectangle:
Area = Length x Height , Given area = 25 m².
Now, from the figure:
-
-
The Height of Triangle as per above calculation is 5 meters.
-
Then the Lengh will be
-
Length = Area / Height
- Height = 25 / 5 = 5 Meters
-
Find the Width of the Blue Rectangle
Next, let’s calculate the Length of the blue rectangle.
-
The combined width of the First rectangle and blue rectangle at the top is 7 meters.
-
The Length of the First rectangle alone is 4 meters.
So, Length of blue rectangle = 7.00 – 4.00 = 3.00 Meters
3. Calculate the Area of the Blue Rectangle
-
Length = 3 meters
-
Height = 5 meters
Area = Length x Height
✅ So, the area of the blue rectangle is 15 square meters.

Understood clearly