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]. Car A drives on Main Street for 14 miles to arrive at Oak Street. How far will Car B 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 :

Let's solve this problem step by step.

1. Understanding the relationship given by the tangent:
- We are given that tan [tex]\( y' = \frac{5}{7} \)[/tex].
- The tangent of an angle in a right triangle is the ratio of the length of the opposite side to the length of the adjacent side.

2. Assign the given values:
- Car A travels along Main Street, which forms the adjacent side of the right triangle. The length of the adjacent side (Main Street) is 14 miles.
- We need to find the length of the opposite side (First Street) for Car B to reach Oak Street.

3. Use the definition of tangent:
[tex]\[ \tan(y') = \frac{\text{opposite}}{\text{adjacent}} \][/tex]
Since we know that [tex]\(\tan(y') = \frac{5}{7}\)[/tex], the adjacent side is 14 miles, and we denote the opposite side (the distance Car B needs to travel) as [tex]\( x \)[/tex]:

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

4. Solve for [tex]\( x \)[/tex]:
We can solve the equation for [tex]\( x \)[/tex] by multiplying both sides by 14:

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

5. Calculation:
[tex]\[ x = 14 \times 0.7142857142857143 \][/tex]
[tex]\[ x = 10 \][/tex]

6. Finalize the answer:
The distance Car B has to travel on First Street to get to Oak Street is 10 miles. When we round this to the nearest tenth, it remains 10.0 miles.

So, Car B will have to travel 10 miles on First Street to get to Oak Street. The correct choice from the given options is:

- 10 miles