X = 1581.13883 is your answer
The diameter is the line that goes through the middle of a circle and the radius goes from the center to a point in the circle so r = d/2 or d =2r
C. d/2
C = π×D
D = C/π = (5.3 mm)/π ≈ 1.69 mm
Answer:
We know that this triangle is similar because it will have all of the same angles as the first triangle. This is because two parallel lines cut by a transversal will create the same angles. In addition, they share the final angle because we are not changing that angle. Therefore, all 3 are the same, which makes them similar triangles.
Recall the double angle identity:
With 
measuring between 0º and 90º, we know 
. So from the Pythagorean identity, we get
Then
