Answer:
- area of rectangle: 48 cm²
- area of triangle: 18 cm²
- shaded area: 30 cm²
Explanation:
The area of a rectangle is given by the product of its length and width.
... A = LW
For your rectangle, the overall area is ...
... A = (12 cm)(4 cm) = 48 cm² . . . . rectangle area
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The area of a triangle is half the product of its base and height. Your triangle is shown with a base of 9 cm, and its height is the height of the rectangle, 4 cm. The triangle area is ...
... A = (1/2)bh
... A = (1/2)(9 cm)(4 cm) = 18 cm² . . . . triangle area
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The shaded area of the figure is the difference between the rectangle area and the triangle area. (The triangle is fully included in the rectangle, but is not shaded.) That difference is ...
... shaded area = rectangle area - triangle area
... shaded area = 48 cm² - 18 cm² = 30 cm² . . . . shaded area