42.4 2 1111
Exercise
1.Find the volumes of the isosceles tetrahedra with face given below:ab c V
11 20 21
33 65 72
69 91 100
21 99 100
2.Find the volumes of the following tetrahedra:abca
′
b
′
c
′
V
32 33 35 76 70 44
21 32 47 58 76 56
3.What is the shape of the envelope in Twigg’s model for which the
resulting tetrahedron is regular?4.In Twigg’s envelope model, supposeAB =2aandBC =2b.
What is the volume of the resulting tetrahedron?^3(^3) This is an isosceles tetrahedron with face 2 a,√a (^2) +b (^2) , and√a (^2) +b (^2). Its volume is (^49) a 2 √b (^2) −a (^2).