Math Problem Statement

Calculate the shaded area of a rectangle with dimensions 8 cm by 8 cm, from which a triangular section of height 4 cm and base 8 cm is removed.

Solution

Let's break this problem down step by step.

Given:

  • The outer shape is a rectangle.
  • The dimensions of the rectangle are 8 cm in height and an unknown width (assumed to be same as height, 8 cm).
  • A triangular section is removed from the bottom, with a height of 4 cm and a base equal to the width of the rectangle (8 cm).

Step 1: Calculate the Area of the Rectangle

Arectangle=width×height=8×8=64 cm2A_{\text{rectangle}} = \text{width} \times \text{height} = 8 \times 8 = 64 \text{ cm}^2

Step 2: Calculate the Area of the Triangle

The area of a triangle is given by: Atriangle=12×base×heightA_{\text{triangle}} = \frac{1}{2} \times \text{base} \times \text{height} Substituting values: Atriangle=12×8×4=322=16 cm2A_{\text{triangle}} = \frac{1}{2} \times 8 \times 4 = \frac{32}{2} = 16 \text{ cm}^2

Step 3: Calculate the Shaded Area

Ashaded=ArectangleAtriangleA_{\text{shaded}} = A_{\text{rectangle}} - A_{\text{triangle}} Ashaded=6416=48 cm2A_{\text{shaded}} = 64 - 16 = 48 \text{ cm}^2

Final Answer:

The shaded area is 48 cm².

Would you like a more detailed explanation or any variations on this problem?


Related Questions:

  1. How would the shaded area change if the triangle's height was 6 cm instead of 4 cm?
  2. What is the perimeter of the shaded region?
  3. How can we generalize this method for different rectangle and triangle sizes?
  4. If the rectangle was a square with side x, how would the shaded area be expressed in terms of x?
  5. How can this problem be solved using algebraic expressions?

Tip:

Always double-check whether the removed shape is completely inside the larger shape to ensure correct subtraction of areas.

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Math Problem Analysis

Mathematical Concepts

Geometry
Area Calculation

Formulas

Area of rectangle = width × height
Area of triangle = (1/2) × base × height

Theorems

Area subtraction for composite shapes

Suitable Grade Level

Grades 6-8