Cho a//b và c vuông góc với a a/ Đường thẳng c có vuông góc với đường thẳng b không Vì saoBài 2: Cho biết a//b <!--[if gte vml 1]> id="_x0000_t75" coordsize="21600,21600" o:spt="75" o:preferrelative="t" a) Đường thẳng c <!--[if gte vml 1]> id="Picture_x0020_23" o:spid="_x0000_i1033" type="#_x0000_t75" alt="Description: C:\\\\Users\\\\ASUS\\\\AppData\\\\Local\\\\Temp\\\\ksohtml2000\\\\wps68.png" > b) Cho đường thẳng d <!--[if gte vml 1]> id="Picture_x0020_21" o:spid="_x0000_i1031" type="#_x0000_t75" alt="Description: C:\\\\Users\\\\ASUS\\\\AppData\\\\Local\\\\Temp\\\\ksohtml2000\\\\wps70.png" > Bài 3. Cho hình vẽ sau, biết rằng a) Tính góc ABE<!--[if gte vml 1]> id="Picture_x0020_13" o:spid="_x0000_i1027" type="#_x0000_t75" alt="Description: C:\\\\Users\\\\ASUS\\\\AppData\\\\Local\\\\Temp\\\\ksohtml2000\\\\wps84.png" > b) Chứng minh Cy//Ax<!--[if gte vml 1]> id="Picture_x0020_12" o:spid="_x0000_i1026" type="#_x0000_t75" alt="Description: C:\\\\Users\\\\ASUS\\\\AppData\\\\Local\\\\Temp\\\\ksohtml2000\\\\wps85.png" > c) Chứng minh AB vuông góc với BC<!--[if gte vml 1]> id="Picture_x0020_11" o:spid="_x0000_i1025" type="#_x0000_t75" alt="Description: C:\\\\Users\\\\ASUS\\\\AppData\\\\Local\\\\Temp\\\\ksohtml2000\\\\wps86.png" > <!--[if gte vml 1]> id="Picture_x0020_15" o:spid="_x0000_i1025" type="#_x0000_t75" alt="Description: C:\\\\Users\\\\ASUS\\\\AppData\\\\Local\\\\Temp\\\\ksohtml2000\\\\wps76.png" > |