DEFINITIONS, 



acute, or obtuse angle. If the contained angle be 

 less than a right angle, the triangle is called acute, 

 but if greater, it is called obtuse. The line on which 

 c is placed is called the &ase of the triangle. 





Fig. 5. 



A scalene triangle, fig. 5, has three unequal sides, 

 and contains three unequal angles. 



Fig. 6. 



A square, fig. 6, has four equal sides, containing 

 four right angles. 



Fig. 7. 



A rectangle, fig. 7, has its adjacent sides, a and b, 

 unequal, the four contained angles being right angles. 



Fig. 8. 



A rhomb, fig. 8, has four equal sides, but its ad- 

 jacent angles, a and b, unequal. 



