直角是一个爱探险的小王子.听说新近发现了一个有水怪的湖泊——平行线湖,这引起了直角的极大兴趣,这不,他又备好行装,前往探险.下面是他传回的探险实况录像,让我们一起来仔细收看吧!探险第一关:直角顶点在一对平行线中的某一条上,已知角在直角三角形外部,探求角的度数.例1(2011年泰安)如图1,l//m,等腰直角三角形ABC的直角顶点C在直线m上, Right angle is a love of the little prince.I heard that a recently discovered a monster lake - parallel to the lake, which aroused great interest at right angles, this is not, he was ready to travel, to adventure. Expedition live video, let’s watch it together! Adventure first pass: Right angle vertex in a pair of parallel lines in a certain line, the known angle outside the right triangle, to explore the angle of the degree.Example 1 (2011 Taian) Figure 1, l / m, isosceles right triangle ABC right angle vertex C in the straight line m,