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Finding the Fourth Proportional to 20,811, 28,719.30 and 13,359

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Solution

The fourth proportional to 20,811, 28,719.30 and 13,359 is: 18,435.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    20,811 : 28,719.30 = 13,359 : x
  2. Step 2: Convert to fraction form
    20,811/28,719.30 = 13,359/x
  3. Step 3: Cross multiply
    20,811x = 28,719.30 × 13,359
  4. Step 4: Simplify right side
    20,811x = 383,661,128.70
  5. Step 5: Solve for x
    x = 383,661,128.70/20,811
  6. Step 6: Final answer
    x = 18,435.50

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.