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Finding the Fourth Proportional to 687.87, 1,031.80 and 551.77

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Solution

The fourth proportional to 687.87, 1,031.80 and 551.77 is: 827.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.87 : 1,031.80 = 551.77 : x
  2. Step 2: Convert to fraction form
    687.87/1,031.80 = 551.77/x
  3. Step 3: Cross multiply
    687.87x = 1,031.80 × 551.77
  4. Step 4: Simplify right side
    687.87x = 569,316.29
  5. Step 5: Solve for x
    x = 569,316.29/687.87
  6. Step 6: Final answer
    x = 827.65

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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.