The post office is at the corner of First Street and Main Street, which forms a right angle. First Street intersects with Oak Street to the north, and Main Street intersects with Oak Street to the east. The intersection of Main Street and Oak Street forms a [tex]y[/tex] angle, and [tex]\tan y = \frac{5}{7}[/tex]. A car drives on Main Street for 14 miles to arrive at Oak Street. How far will the car have to travel on First Street to get to Oak Street? Round your answer to the nearest tenth of a mile.

A. 5 miles
B. 7.4 miles
C. 10 miles
D. 19.6 miles



Answer :

To solve this problem, let's break it down step by step:

### Step 1: Understand the Given Information
- The post office is at the corner of First Street and Main Street, forming a right angle.
- First Street intersects with Oak Street to the north, and Main Street intersects with Oak Street to the east.
- Main Street and Oak Street form an angle [tex]\( y \)[/tex] where [tex]\( \tan(y) = \frac{5}{7} \)[/tex].
- A car drives on Main Street for 14 miles to arrive at Oak Street.

### Step 2: Solve for the Distance on First Street

We are given the tangent of the angle [tex]\( y \)[/tex], which is the ratio of the length of the opposite side to the adjacent side in a right triangle. Here:

[tex]\[ \tan(y) = \frac{\text{opposite}}{\text{adjacent}} = \frac{5}{7} \][/tex]

In this scenario:
- The "opposite" side corresponds to the distance traveled on First Street.
- The "adjacent" side corresponds to the distance traveled on Main Street, which is 14 miles.

Let's denote the distance traveled on First Street as [tex]\( d \)[/tex].

Since [tex]\( \tan(y) = \frac{d}{14} \)[/tex], we set up the equation:

[tex]\[ \frac{d}{14} = \frac{5}{7} \][/tex]

To find [tex]\( d \)[/tex], we solve:

[tex]\[ d = 14 \times \frac{5}{7} \][/tex]

### Step 3: Calculate the Distance

Now, calculate the distance:

[tex]\[ d = 14 \times \frac{5}{7} = 14 \times 0.7142857142857143 \approx 10.0 \][/tex]

### Step 4: Round the Answer

Since the problem asks us to round the answer to the nearest tenth of a mile, we see that the calculated distance [tex]\( d \)[/tex] is already [tex]\( 10.0 \)[/tex].

### Step 5: Identify the Correct Option

The options are:
- 5 miles
- 7.4 miles
- 10 miles
- 19.6 miles

Given that our rounded distance is [tex]\( 10.0 \)[/tex] miles, the correct option is:
- 10 miles

Thus, car B will have to travel approximately 10 miles on First Street to get to Oak Street.