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Finding the Fourth Proportional to 1,005.40, 1,387.21 and 585.50

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Solution

The fourth proportional to 1,005.40, 1,387.21 and 585.50 is: 807.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,005.40 : 1,387.21 = 585.50 : x
  2. Step 2: Convert to fraction form
    1,005.40/1,387.21 = 585.50/x
  3. Step 3: Cross multiply
    1,005.40x = 1,387.21 × 585.50
  4. Step 4: Simplify right side
    1,005.40x = 812,204.15
  5. Step 5: Solve for x
    x = 812,204.15/1,005.40
  6. Step 6: Final answer
    x = 807.85

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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.