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Finding the Fourth Proportional to 7,122.56, 9,829.20 and 3,978.80

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Solution

The fourth proportional to 7,122.56, 9,829.20 and 3,978.80 is: 5,490.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    7,122.56 : 9,829.20 = 3,978.80 : x
  2. Step 2: Convert to fraction form
    7,122.56/9,829.20 = 3,978.80/x
  3. Step 3: Cross multiply
    7,122.56x = 9,829.20 × 3,978.80
  4. Step 4: Simplify right side
    7,122.56x = 39,108,420.96
  5. Step 5: Solve for x
    x = 39,108,420.96/7,122.56
  6. Step 6: Final answer
    x = 5,490.78

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1.5x scale

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.