Page 35 - Trigonometry
P. 35
The third side B (5, -4) to C (8, 6)
r
X? 5= E? 8=
Y? z4= F? 6=n
The triangle lengths are,
AB (12.7279), AC (12.0416) and BC (10.4403)
Now use the cosine formula to calculate the angles in
the triangle,
2
2
2
2
2
2
+ − 2 + − 2 + − 2
cos −1 [ ] cos −1 [ ] cos −1 [ ]
2 2 2
The keystrokes for these three expressions, using a
multistage calculation are,
31
