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Finding the Fourth Proportional to 687.06, 1,029.80 and 378.74

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Solution

The fourth proportional to 687.06, 1,029.80 and 378.74 is: 567.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.06 : 1,029.80 = 378.74 : x
  2. Step 2: Convert to fraction form
    687.06/1,029.80 = 378.74/x
  3. Step 3: Cross multiply
    687.06x = 1,029.80 × 378.74
  4. Step 4: Simplify right side
    687.06x = 390,029.97
  5. Step 5: Solve for x
    x = 390,029.97/687.06
  6. Step 6: Final answer
    x = 567.68

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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.