17.] -- 



>pace equal** * 



he angle between tl..- tun lines. 



I lie projection of any I.I..H.-M line in apace upon any 

 ^lit line equals ""- U|H.II the name lin> 



lino ulurii .ken 



EXERCISES 



1 Two line* of lengths 8 and 7 respectively meet at an angle |; find 

 the projection o( each upon the other. 



2 The center of an equilateral triangle, of side 3, i* Joined by a 

 strai. > a vertex ; find the projection oi ling line upon 

 each side of the 



3. A rectangle has its aides respectively 4 and 6; find their projec- 

 tions upon a diagonal. 



4 Find the length of the projection of each edge of a cube upon 



5. A given !: I /' makes an angle of 30 with the line MX, and 

 in perpendicular to AB and of length 1 the projection of 



Solve this problem if the given angle be a instead of 30. 



6. Two lines in space, of length a and 6 respectively, make an angle 

 > each other; find the projection of >> upon a line that is 



l.ir to a. 



7. Project the perimeter of a square upon one of its diagonals. 



