Answer:
d = 8.5
Explanation:
The following data were obtained from the question:
Angle D = 100°
Opposite D = d
Opposite E = e = 6
Opposite F = f = 5
Thus, we can obtain the value of d by using the cosine rule as shown below:
d² = e² + f² – 2ef Cos D
d² = 6² + 5² – 2 × 6 × 5 × Cos 100°
d² = 36 + 25 – 60 × Cos 100°
d² = 61 – – 10.419
d² = 61 + 10.419
d² = 71.419
Take the square root of both side.
d = √71.419
d = 8.5
Therefore, the value of d is 8.5