Вершини трикутника мають координати А(3;1;2)В(1;2;-1)С(-2;2;1) Доведіть що трикутник АВС прямокутний ,обчисліть площу трикутника АВС​

1. Отношением отрезков AB и CD называется отношение их длин.

2. В треугольниках сходственными сторонами называются те стороны, которые лежат напротив их равных углов.

3. Коэффициентом подобия треугольников называется отношение сходственных сторон подобных треугольников.

4. в) BD/AC=DC/AB

5. Отношение периметров подобных треугольников равно коэффициенту подобия.
1,4 м = 140 см.
k=BC/B₁C₁ = 140/56 = 2.5
ответ: а) 2,5

6. б) параллельной какой-либо стороне 

7. Отношение высот, проведенных к сходственным сторонам подобных треугольников равно отношению сходственных сторон.

8. б) отношению их площадей

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Объяснение:

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