S. L. Penfield — Stereographic P? , ojection. 

 it 



11 



No. I. The angle A is measured on the great circle 2, using 

 protractor No. II, page 18. 

 The results are as follows : 





Calculated. 



Plotted. 



Error 



A = 



98° 21' 



98° 30' 



9' 



B =-- 



76 47 



76 40 



7 



G = 



71 16 



71 15 



1 



Case h. — Given the two sides and the included angle of an 

 oblique triangle, a = 31° 25', h = 88° 53', and C = 97° 13', 

 figure 18. To plot the angle C, on the diameter x locate the 

 point p 97° 13' from the divided circle, and construct the 

 great circle Op. To plot the side a and thus locate B, on 





] 



8 









/ 



— 



~~~-—~? 







p 



y 



V 

 B 





At 





\M 



c 





A) 



