Use the applet below to complete this activity.[br]a) Make an internal angle bisector 内角の二等分線 for angle A.[br]b) Find the point of intersection 交点 between the angle bisector and BC.[br]c) Name the point of intersection D.[br]d) Find the lengths長さ: AB, BD, AC, CD
Calculate the ratios [math]\frac{AB}{BD}[/math] and [math]\frac{AC}{CD}[/math]. What do you notice? Change the triangle by moving the vertices and calculate again. [math]\frac{AB}{BD}[/math]と[math]\frac{AC}{CD}[/math]は、比を計算しなさい。どのようなことがわかりますか？ 頂点を動かして三角形を変え、もう一度計算してみましょう。
Calculate the ratios [math]\frac{AB}{AC}[/math] and [math]\frac{BD}{CD}[/math]. What do you notice? Change the triangle and calculate again.
Use the applet below to complete this activity.[br]a) Make an external angle bisector 外角の二等分線 for angle A.[br]b) Find the point of intersection 交点 between the angle bisector and the line through BC.[br]c) Name the point of intersection D.[br]d) Find the lengths長さ: AB, BD, AC, CD
Calculate the ratios [math]\frac{AB}{BD}[/math] and [math]\frac{AC}{CD}[/math]. What do you notice? Change the triangle by moving the vertices and calculate again. [math]\frac{AB}{BD}[/math]と[math]\frac{AC}{CD}[/math]は、比を計算しなさい。どのようなことがわかりますか？ 頂点を動かして三角形を変え、もう一度計算してみましょう。
In triangle ABC with angle bisector AD, AB:AC=BD:DC