Identify and use the relationship between the radius and a line tangent to the circle, where the radius intersects the circle, to solve the following. If KM¯¯¯¯¯¯¯¯¯¯ and KL¯¯¯¯¯¯¯¯ are tangent to the circle at L and M , ∠LFK=23 degrees , and KM¯¯¯¯¯¯¯¯¯¯=47 feet , how long is LF¯¯¯¯¯¯¯ to the nearest foot?

(1 point)
Responses

111 ft.
111 ft.

20 ft.
20 ft.

120 ft.
120 ft.

51 ft.

1 answer

To find the length of \( LF \), we can use the relationship between a radius and a tangent to a circle. The radius drawn to the point of tangency is perpendicular to the tangent line.

Given:

  • \( KM \) and \( KL \) are tangent to the circle at points \( L \) and \( M \) respectively.
  • \( \angle LFK = 23^\circ \)
  • \( KM = 47 \) feet

Since \( LAP \) (the radius to point L) is perpendicular to \( KL \) (the tangent line), we know that \( \triangle LFK \) is a right triangle with:

  • \( \angle LKF = 90^\circ - \angle LFK = 90^\circ - 23^\circ = 67^\circ \).

Using the tangent ratio (opposite/adjacent):

\[ \tan(\angle LFK) = \frac{LF}{KL} \]

Substituting the known values:

\[ \tan(23^\circ) = \frac{LF}{47} \]

Now, solving for \( LF \):

\[ LF = 47 \cdot \tan(23^\circ) \]

Calculating \( \tan(23^\circ) \):

\[ \tan(23^\circ) \approx 0.4245 \]

Now plug this value back into the equation:

\[ LF \approx 47 \cdot 0.4245 \approx 19.97 \text{ feet} \]

Rounding this to the nearest foot gives \( LF \approx 20 \) feet.

Thus, the correct response is:

20 ft.