ANSWER
The length of a Diameter is 3.714
EXPLANATION
The circumscribed triangle is shown in the attachment.
We use the cosine ratio to find the altitude of the isosceles triangle.


Altitude =8cos(60°)
Altitude=4cm
Let the upper half of the altitude be y cm.
Then the radius of the circle is (y-4)cm
The upper radius meets the tangent at right angles.
From the smaller right triangle,






y=1.857
The diameter is 2y

=2(1.875)
The length of a Diameter is 3.714
Answer:
If line EF was dilated by a scale of 1/2 from the origin to get line E'F', then if line E'F' is dilated by a scale of 2 from the origin, EF is obtained. Also, the length of EF is double than the length of E'F'.
Dilation by a scale of 2 from the origin transforms point (x,y) into (2*x, 2*y)
E'(1,0) -> E(2,0)
F'(1, 3) ->F(2, 6)
length of E'F': 3
length of EF: 6
The answer that i got for your question is the first answer.
Answer:
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