Math Problem Statement

In circle P, chords AB and CD intersect at E so that Ad=AE=3, ED = 4 and BC = 5. What is the area of triangle EBC? Express your answer as a common fraction in simplest radical form. use inscribed theorem to simplify your solution.

Solution

We are given a circle PP with chords ABAB and CDCD intersecting at point EE. We are also given the following measurements:

  • AD=AE=3AD = AE = 3
  • ED=4ED = 4
  • BC=5BC = 5

Our goal is to find the area of triangle EBCEBC.

Step 1: Use the Power of a Point Theorem

The Power of a Point Theorem states that for two intersecting chords, the products of the segments of each chord are equal. Specifically, for the chords ABAB and CDCD intersecting at point EE, we have the following relation:

AE×EB=CE×EDAE \times EB = CE \times ED

We are given AE=3AE = 3, AD=AE=3AD = AE = 3, and ED=4ED = 4. We do not yet know the lengths of EBEB and CECE, but we can express them in terms of each other using the Power of a Point.

Let EB=xEB = x and CE=yCE = y. Then from the Power of a Point Theorem, we have:

3×x=y×43 \times x = y \times 4

Simplifying this equation:

3x=4y3x = 4y x=43y(Equation 1)x = \frac{4}{3}y \quad \text{(Equation 1)}

Step 2: Apply the Length of Chord BCBC

We are also given the length of chord BCBC, which is 55. Since BC=BE+ECBC = BE + EC, we have:

BE+EC=5BE + EC = 5 x+y=5(Equation 2)x + y = 5 \quad \text{(Equation 2)}

Step 3: Solve the System of Equations

Now, we solve the system of equations (Equation 1 and Equation 2):

  1. x=43yx = \frac{4}{3}y
  2. x+y=5x + y = 5

Substitute x=43yx = \frac{4}{3}y into the second equation:

43y+y=5\frac{4}{3}y + y = 5

Combine the terms on the left-hand side:

43y+33y=5\frac{4}{3}y + \frac{3}{3}y = 5 73y=5\frac{7}{3}y = 5

Multiply both sides by 3 to eliminate the fraction:

7y=157y = 15 y=157y = \frac{15}{7}

Now substitute y=157y = \frac{15}{7} back into x=43yx = \frac{4}{3}y:

x=43×157=6021=207x = \frac{4}{3} \times \frac{15}{7} = \frac{60}{21} = \frac{20}{7}

So, x=207x = \frac{20}{7} and y=157y = \frac{15}{7}.

Step 4: Find the Area of Triangle EBCEBC

The area of triangle EBCEBC can be found using the formula for the area of a triangle with base BCBC and height EDED. The base of triangle EBCEBC is BC=5BC = 5, and the height is the perpendicular distance from EE to the line BCBC, which is the length ED=4ED = 4.

The area of triangle EBCEBC is:

Area=12×base×height=12×5×4=10\text{Area} = \frac{1}{2} \times \text{base} \times \text{height} = \frac{1}{2} \times 5 \times 4 = 10

Thus, the area of triangle EBCEBC is 10\boxed{10}.

Would you like further clarification or more details? Here are some related questions:

  1. How does the Power of a Point Theorem apply to other geometric shapes?
  2. Can the Power of a Point Theorem be used to find lengths in tangents to circles?
  3. How do you calculate the area of a triangle when given the lengths of all sides?
  4. What other methods can be used to calculate areas of triangles in coordinate geometry?
  5. How do intersecting chords relate to the properties of inscribed angles?

Tip: When solving problems involving intersecting chords, always start by applying the Power of a Point Theorem, as it can simplify the relations between the segments of the chords.

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Math Problem Analysis

Mathematical Concepts

Geometry
Circle Theorems
Area of a Triangle
Power of a Point

Formulas

Power of a Point: AE × EB = CE × ED
Area of a Triangle: (1/2) × base × height

Theorems

Power of a Point Theorem
Inscribed Theorem

Suitable Grade Level

Grades 9-12