Another purportedly hard geometry puzzle
<p>One can rotate <em>Figure 1</em> anticlockwise by 90° and flip it horizontally without changing the radius of the smaller circle. The hope is that this will make the problem easier to solve. This is <em>Figure 3</em> below.</p>
<p><img alt="A circle is nestled between three curves on the positive x y plane. First, the concave edge of a circle of radius one centred at the origin. Second, the convex edge of the curve y equals x squared. Third, the x axis. What is the radius of the circle?" src="https://miro.medium.com/v2/resize:fit:700/1*eLpJYFVM7OrDFg5UmwJeEQ.png" style="height:640px; width:700px" /></p>
<p>Figure 3: Rotated and flipped version of the problem</p>
<p>Notice how √<em>x </em>has become <em>x²</em>. That’s because rotating switches the <em>x</em> and <em>y</em> for each other. It problem suddenly looks much better! Now, let’s name some points of interest. These are shown in <em>Figure 4</em>.</p>
<p>These points of interest are the following: the centre (<em>a, b</em>) and radius (<em>r</em>)<em> </em>of our circle (the smaller circle), and the three points of tangency ((<em>a1, a2</em>), (<em>b1, b2</em>) and (<em>c1, c2</em>)) of the three curves that form tangents with our circle respectively.</p>
<p><a href="https://dheerajdhobley.medium.com/another-purportedly-hard-geometry-puzzle-784c1b84b0a4"><strong>Click Here</strong></a></p>