Respuesta :

Answer:

77°

Step-by-step explanation:

By the property of intersecting tangent and secant outside of a circle:

[tex]21 \degree = \frac{1}{2} ( 119 \degree - \widehat{SU} ) \\ \\ 42 \degree = 119 \degree - \widehat{SU} \\ \\ \widehat{SU} =119 \degree - 42 \degree \\ \\ \widehat{SU} =77\degree \\ \\ [/tex]

The mArc SU is option (B) 77 degrees

What is Tangent?

A straight line or plane that touches a curve or curved surface at a point, but if extended does not cross it at that point.

What is secant ?

A secant is a line that intersects a circle in exactly two points.

Here,

By the property of intersecting tangent and secant outside of a circle:

[tex]T=\frac{1}{2}(RU-SU)[/tex]

Here

T= 21 degrees

RU is the mArc RU = 119 degrees

Then,

[tex]21 =\frac{1}{2}(119-SU)\\ 42=119-SU\\SU=119-42[/tex]

SU = 77 degrees

Hence, the mArc SU is option (B) 77 degrees

Learn more about Tangent and secant here

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