Given 3 Sides: Self-check Applet

① This applet demonstrates how to construct a unique triangle when three side lengths are given, and includes a self-check feature to verify that the constructed triangle satisfies the side-length conditions. ② The core mathematical concepts are the triangle inequality theorem and classical geometric construction using circles and intersections. ③ Construction details: using GeoGebra commands such as Segment to create the three given side lengths, Circle to draw circles centered at endpoints with radii equal to the other two sides, Intersect to find the intersection point of the two circles, and Polygon to form the triangle; text objects (text1, text2, text3) display side lengths and self-check results, and a target object is used for dynamic verification. ④ Suitable for middle school geometry lessons or self-study, helping students intuitively understand the triangle side conditions (sum of any two sides greater than the third) and the rigor of geometric construction, also useful for teacher demonstrations or student practice.