4'->»' 



GEOMETRT. 



PROBLEM XIXo 



21? inscribe an isosceles triangle in a given circle, that shall 

 have each of the angles at the base double the angle at the 



vertex. 



Draw any diameter A B of the givers 

 circle ; and divide the radius CB, in the 

 point D, in extreme and mean ratio, by 

 the last problem. From the point B 

 apply the chords BE, BF, each equal to 

 C D 'y then join A E, A F, E F, and 

 A E F will be the triangle required. 



PROBLEM XX« 



To male an enu'ilateral Triangle on a given Line A.b. 



From the centred A and B, 

 with the radius A B, describe 

 arcs intersecting in C. Draw 

 A C and B C^ and it is dene. 



Note. An isosceles trian;^Ie may be made in the same 

 manner, by taking for the radius the given length of one 

 ef the equal sides. 



PROBLEM 



