Besties pls help

8) In the diagram below, what is the m measure of R.

Let's see what we can fill in here.

<ACE = 130

180 - 50 = 130

Now that we have two sides and an included angle, we can use the Law of Cosines.

Law of Cosines: c^2 = a^2 + b^2 - 2ab(cos(C))

Let's plug in what we know and solve!

c^2 = 40^2 + 38^2 - 2(40)(38)(cos(130))

R = 70.69706

Hope this helps!! :)

R =70.6970629

Step-by-step explanation:

We need to use the law of cosines since we have 2 sides and the included angle

The angle inside is 180 -50 = 130

c^2 = a^2 + b^2 − 2ab cos(C)  where c is the side opposite the unknown angle

R^2 = 40^2 + 38^2 - 2*40 *38 cos (130)

R^2 = 1600 -1444-3040cos 130

R^2 = 3044-3040cos130

R^2 =4998.074333

Taking the square root of each side

sqrt(R^2) = sqrt( 4998.074333)

R =70.6970629