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Finding the Fourth Proportional to 1,387.72, 2,080.12 and 656.76

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Solution

The fourth proportional to 1,387.72, 2,080.12 and 656.76 is: 984.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,387.72 : 2,080.12 = 656.76 : x
  2. Step 2: Convert to fraction form
    1,387.72/2,080.12 = 656.76/x
  3. Step 3: Cross multiply
    1,387.72x = 2,080.12 × 656.76
  4. Step 4: Simplify right side
    1,387.72x = 1,366,139.61
  5. Step 5: Solve for x
    x = 1,366,139.61/1,387.72
  6. Step 6: Final answer
    x = 984.45

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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.