16. Which of the following are the measures of a right isosceles triangle?
a. 36°, 60°, 90°
b. 40°, 40°, 90°
c. 60°, 60°, 60°
d. 45°, 90°, 45°
17. Of the following triangles, which one is impossible to construct?
a. acute scalene
b. acute equilateral
c. obtuse scalene
d. obtuse equilateral