HKMO1314GCQ1

Figure 1 shows a [math]\Delta[/math]ABC . Construct a circle with centre O inside the triangle such that the three sides of the triangle are tangents to the circle. 圖一所示為一個 [math]\Delta[/math]ABC 。試在該三角形內，構作一個圓心為 O 的圓，使三 角形三條邊均為該圓的切線。