Question

A small radio transmitter broadcasts in a 40 mile radius. If you drive along a straight line from a city 55

miles north of the transmitter to a second city 51 miles east of the transmitter, during how much of the
drive will you pick up a signal from the transmitter?
miles

Answer 1

We can use the Pythagorean theorem to find the distance between the transmitter and the second city:

c² = a² + b²

c² = 55² + 51²

c² = 3026

c ≈ 55.01

So the transmitter is about 55.01 miles away from the second city.

To determine how much of the drive will pick up a signal, we can draw a circle with a radius of 40 miles centered at the transmitter, and see which part of the line connecting the two cities is within this circle.

We can see that the line connecting the two cities intersects the circle at two points, forming a right triangle with one leg measuring 40 miles. We can use trigonometry to find the length of the other leg:

sin(theta) = opposite/hypotenuse

sin(theta) = 40/c

csin(theta) = 40

a = csin(theta)

a = 55.01*sin(theta)

Now we need to find the angle theta, which can be found using inverse tangent:

tan(theta) = opposite/adjacent

tan(theta) = 55/51

theta = tan⁻¹(55/51)

theta ≈ 49.72 degrees

So we can substitute this value of theta into the equation we found earlier for a:

a ≈ 43.89

Therefore, the length of the line segment within the circle is approximately 43.89 miles. To find the length of the entire line segment connecting the two cities, we can use the Pythagorean theorem again:

b² = c² - a²

b² = 55.01² - 43.89²

b ≈ 33.6

So the entire length of the line segment connecting the two cities is approximately 33.6 miles. Therefore, the portion of the drive during which you will pick up a signal from the transmitter is 43.89/33.6 = 1.31 hours or about 79 minutes.