Try this beautiful problem from Geometry based on Semicircle.
A $1\times 2$ rectangle is inscribed in a semicircle with the longer side on the diameter. What is the area of the semicircle?
Geometry
Square
semi circle
Answer:\(\pi\)
AMC-8 (2013) Problem 20
Pre College Mathematics
At first we have to find out the radius of the semicircle for the area of the semicircle.Now in the diagram,AC is the radius of the semicircle and also AC is the hypotenuse of the right Triangle ABC.
Can you now finish the problem ..........
Now AB=1 AND AC=1 (As ABDE $1\times 2$ rectangle .So using pythagorean theorm we can eassily get the value of AC .and area of semicircle =\(\frac{\pi r^2}{2}\)
can you finish the problem........
Given that ABDE is a square whose AB=1 and BD=2
Therefore BC=1
Clearly AC be the radius of the given semi circle
From the \(\triangle ABC\),\((AB)^2+(BC)^2=(AC)^2\Rightarrow AC=\sqrt{(1^2+1^2)}=\sqrt2\)
Therefore the area of the semicircle=\(\frac{1}{2}\times \pi(\sqrt 2)^2\)=\(\pi\)
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