Geometric Probability in a Triangle

MathematicsGeometric ProbabilityHardSTEM

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Q5: A triangle has sides of lengths 3, 7, and 8. What is the probability of the randomly chosen point in the triangle has less distance than 1 to at least one of it's corners? A) $\frac{\pi\sqrt{2}}{36}$ B) $\frac{\pi\sqrt{3}}{36}$ C) $\frac{\pi}{36}$ D) $\frac{1}{2}$ E) $\frac{3}{4}$

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Step 1

Hi Serkan, let's solve this geometric probability problem together. We need to find the probability that a point chosen inside a specific triangle is close to one of its corners.

Problem Analysis

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Step 2

A random point chosen in a region follows a uniform distribution, so the probability is simply the ratio of the favorable area to the total area of the triangle.

$$P = \frac{\text{Area of favorable region}}{\text{Total Area of triangle}}$$
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Step 3

Let's start by finding the total area of the triangle with sides 3, 7, and 8. We can use Heron's formula for this.

1. Area of the Triangle

$$\text{Area} = \sqrt{s(s-a)(s-b)(s-c)}$$
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Step 4

First, we calculate the semi-perimeter, s, which is the sum of the sides divided by two.

$$s = \frac{3 + 7 + 8}{2} = 9$$
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Step 5

Now we plug the values into the area formula: 9 times 9 minus 3, times 9 minus 7, times 9 minus 8.

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Step 6

This simplifies to the square root of 9 times 6 times 2 times 1, which equals the square root of 108.

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Step 7

Next, let's identify the favorable region. These are points with a distance less than 1 from at least one corner.

2. Favorable Region

c=8a=3b=7
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Step 8

This region consists of three circular sectors centered at the vertices, each with a radius of 1. Since the shortest side is 3, these sectors do not overlap.

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About This Question

Subject
Mathematics
Topic
Geometric Probability
Difficulty
Hard
Exam
STEM
Question Type
Multiple Choice

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