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With O as the origin, let's assume the circle to be: x²+ y² = R² and point P to be (a,b). Likewise, let Q be (q,0) & S be (p,R). Now it will be adequate to show that p=q for ASQO to be a rectangle. The tangent at P is:ax+by=R² and this meets the tangent at A with p as given by: ap +bR=R² or p =R(R-b)/a. By similarity, we further claim that: R/(R+b) = q/a or q=aR/(R+b). Now p=q if R(R-b)/a = aR/(R+b) or if (R--b)(R+b) = a² or if R² - b² = a² or if a² + b² = R² which is true since P:(a,b) lies on the circle; hence p = q. In other words, ASQO is rectangular.
Easy Math Editor
This discussion board is a place to discuss our Daily Challenges and the math and science related to those challenges. Explanations are more than just a solution — they should explain the steps and thinking strategies that you used to obtain the solution. Comments should further the discussion of math and science.
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What is "mesoparallili"?
Since ∠OPS=90∘ and ∠OAS=90∘, hence ASPO is a cyclic quad.
Since ∠PAB=90∘−∠PBA=∠PQO=180∘−∠OQP, hence APQO is a cyclic quad.
Hence, ASPQO is a cyclic quad. Thus, since ∠SAO=90∘, hence ∠SQO=90∘. And since ∠AOQ=90∘ hence ∠ASQ=90∘. So we have ASQO is a rectangle.
With O as the origin, let's assume the circle to be: x²+ y² = R² and point P to be (a,b). Likewise, let Q be (q,0) & S be (p,R). Now it will be adequate to show that p=q for ASQO to be a rectangle. The tangent at P is:ax+by=R² and this meets the tangent at A with p as given by: ap +bR=R² or p =R(R-b)/a. By similarity, we further claim that: R/(R+b) = q/a or q=aR/(R+b). Now p=q if R(R-b)/a = aR/(R+b) or if (R--b)(R+b) = a² or if R² - b² = a² or if a² + b² = R² which is true since P:(a,b) lies on the circle; hence p = q. In other words, ASQO is rectangular.