A square is inscribed in a semi circle of radius 10 cm. What is the ar...
Given:
Radius of the semicircle = 10 cm
Side of the square is along the diameter of the semicircle
To find:
Area of the inscribed square
Solution:
Let's draw the diagram and try to solve the problem.
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1. Draw a semicircle of radius 10 cm.
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2. Draw a diameter of the semicircle. Let's call it AB.
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3. Draw a square ABCD with AB as one of its sides.
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4. Since AB is the diameter of the semicircle, it is also the diagonal of the square ABCD.
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5. Let's find the length of the side of the square.
Using Pythagoras theorem,
AB² = BC² + AC²
AB² = 10² + BC²
Since ABCD is a square, BC = CD = DA
AB² = 10² + BC² + BC²
AB² = 10² + 2BC²
BC² = (AB² - 10²)/2
BC = (AB² - 10²)/2√2
But AB = side of the square
Side of the square = (AB² - 10²)/2√2
Side of the square = (20² - 10²)/2√2
Side of the square = 10√2 cm
6. Now, we can find the area of the square.
Area of the square = (Side of the square)²
Area of the square = (10√2)²
Area of the square = 100 x 2
Area of the square = 200 cm²
Therefore, the area of the inscribed square is 200 cm².
Hence, the correct option is (D) 80 cm².