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Finding the Fourth Proportional to 12,289, 18,420.78 and 4,890.28

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Solution

The fourth proportional to 12,289, 18,420.78 and 4,890.28 is: 7,330.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    12,289 : 18,420.78 = 4,890.28 : x
  2. Step 2: Convert to fraction form
    12,289/18,420.78 = 4,890.28/x
  3. Step 3: Cross multiply
    12,289x = 18,420.78 × 4,890.28
  4. Step 4: Simplify right side
    12,289x = 90,082,772.02
  5. Step 5: Solve for x
    x = 90,082,772.02/12,289
  6. Step 6: Final answer
    x = 7,330.36

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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.