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Finding the Fourth Proportional to 754.40, 1,038.87 and 643.83

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Solution

The fourth proportional to 754.40, 1,038.87 and 643.83 is: 886.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    754.40 : 1,038.87 = 643.83 : x
  2. Step 2: Convert to fraction form
    754.40/1,038.87 = 643.83/x
  3. Step 3: Cross multiply
    754.40x = 1,038.87 × 643.83
  4. Step 4: Simplify right side
    754.40x = 668,855.67
  5. Step 5: Solve for x
    x = 668,855.67/754.40
  6. Step 6: Final answer
    x = 886.61

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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.