OKOMKi 



-ed in a parenthe> t w the 



hieh OM 4 and MP h \ while tin- j 

 l 



22. Rectangular coordinates. The simplest and tiKJHt 

 mon rtesian coordinate axes is that in \\in.-h the 



angle A") -a positive right 

 angle; the abscissa (y> of a 



. in this case, its perpen- n 



//axis, 



and ita ordinate (y) is iU perpen- 



l 

 Thin way of locating the poiir 



Ill 



} 





IV 



of a plane is known as the rec 

 tangular system of coordinates. 



i\rs diM.ii- tin- <nt ire plane into four parts called quad- 

 rants, which are usually designated as first (I), second (II), 

 third (III), and fourth < I \ >. in the order of rotation t 

 the po.sitixe end of t; ward the positive end of the 



y-axis, as indicated in the accompanying fign 



These quadrants are distinguished by the ttpii* of the 

 coordinates of the p< n.i; \\ithin them, th,. 



in quadnint I the abscissa (*) is + , the ordinate (y) is + ; 



in quadrant II the abscissa ( . the ordinate ( 



in qu,i<lr.int III the abscissa i .th.-.-rdin. -; 



in quadnint 1 V ; :, abscissa (x) is + , the ordinate (y) is . 



11 points having numerically the same coordinates, hut 

 ; MIL- m each quadrant, are symmetrical in pairs with 

 regard to the origin. lou^h the axes are not at riirht 



angles; if, however, the axes are rectangular, then these 

 points are symmetrical in pairs, not merely with regard to 

 tin- origin as i,,-t, ,:-,-. hut also with regard to the axes, and 



