If the radius of circle D is 5, find AB. Round your answer to the nearest tenth.
6.8
7.7
8.1
8.6

The answer is option 2.

Step-by-step explanation:

Using Cosine Rule, c² = a²+b²-2(a)(b)cosθ where a,b and c represents the side length :

Let a = AD = 5 units (radius),

Let b = BD = 5 units (radius),

Let c = AB,

Let θ = 100°,

c² = 5² + 5² - 2(5)(5)cos 100°

c² = 50 - 50cos 100°

c² = 58.68

c = √58.68

= 7.7 units (near. tenth)

fist on the left goes with the third on the right. second on the left goes with the fourth on the right. third on the left goes with the second on the right. the fourth on the left goes with first on the right