Math Problem Statement

If ab=16cm,bc=20cm and ac=24cm.find ad and bd

Solution

To find the lengths of ADAD and BDBD, we'll use the property of similar triangles, which we established earlier:

  • Given: ABCADC\triangle ABC \sim \triangle ADC (from the previous problem).
  • Known lengths:
    • AB=16cmAB = 16 \, \text{cm}
    • BC=20cmBC = 20 \, \text{cm}
    • AC=24cmAC = 24 \, \text{cm}

Since the triangles ABC\triangle ABC and ADC\triangle ADC are similar, their corresponding sides are proportional:

ABAD=BCCD=ACAC\frac{AB}{AD} = \frac{BC}{CD} = \frac{AC}{AC}

However, since the lengths BCBC and ACAC are on different triangles, we'll actually use the similar triangles condition with the segments:

ABAD=BCBD=ACCD\frac{AB}{AD} = \frac{BC}{BD} = \frac{AC}{CD}

Step 1: Express BDBD and CDCD

Let's denote BD=xBD = x and CD=yCD = y.

From ABAD=BCBD\frac{AB}{AD} = \frac{BC}{BD}:

16AD=20x\frac{16}{AD} = \frac{20}{x}

Similarly, from ABAD=ACCD\frac{AB}{AD} = \frac{AC}{CD}:

16AD=24y\frac{16}{AD} = \frac{24}{y}

But we know AD=AB+BDAD = AB + BD, and AB=16AB = 16 cm.

Step 2: Solve the system of equations

  1. 16AD=20x\frac{16}{AD} = \frac{20}{x}

    AD=16x20=4x5AD = \frac{16x}{20} = \frac{4x}{5}

  2. 16AD=24y\frac{16}{AD} = \frac{24}{y}

    AD=16y24=2y3AD = \frac{16y}{24} = \frac{2y}{3}

Since AD=AB+BDAD = AB + BD, substitute:

4x5=16+x\frac{4x}{5} = 16 + x

Solving for xx (i.e., BDBD):

4x=80+5x4x = 80 + 5x

x=80x = 80

So, BD=80BD = 80 cm.

Similarly, solve for yy using the second equation:

2y3=24+y\frac{2y}{3} = 24 + y

2y=72+3y2y = 72 + 3y

y=72y = 72

Thus, CD=72CD = 72 cm.

Since the two triangles are similar, and we assumed the triangle sides might be overlapping or continuing, you should check with your diagram to ensure that the results match the physical lengths.

But if BDBD and CDCD are considered external, and ADAD is shorter:

Given that AB=16AB = 16, AD=same as BD using similar proportions=201624=30AD = \text{same as BD using similar proportions} = \frac{20}{16}*24=30.

Then you would use the simple side lengths for final proportions.


Would you like more details or have any questions?

Here are some related questions to expand on this concept:

  1. How do we apply the Pythagorean theorem in these cases?
  2. How can we use trigonometric identities to find missing side lengths?
  3. How do we apply properties of right triangles to find ADAD and BDBD?
  4. What are other methods to determine segment lengths in similar triangles?
  5. Can ADAD and BDBD be determined using coordinate geometry?
  6. How does the concept of ratios apply in these triangle segments?
  7. What are some real-life applications of similar triangles?
  8. Can ADAD and BDBD be found using vector algebra?

Tip: Always verify with similar triangle properties that all proportions match when solving for unknown lengths in complex geometric figures.

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Math Problem Analysis

Mathematical Concepts

Geometry
Similar Triangles
Proportions

Formulas

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Theorems

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Suitable Grade Level

Grades 9-12