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Finding the Fourth Proportional to 1,005.45, 1,387.56 and 612.20

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Solution

The fourth proportional to 1,005.45, 1,387.56 and 612.20 is: 844.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,005.45 : 1,387.56 = 612.20 : x
  2. Step 2: Convert to fraction form
    1,005.45/1,387.56 = 612.20/x
  3. Step 3: Cross multiply
    1,005.45x = 1,387.56 × 612.20
  4. Step 4: Simplify right side
    1,005.45x = 849,457.29
  5. Step 5: Solve for x
    x = 849,457.29/1,005.45
  6. Step 6: Final answer
    x = 844.85

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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.