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Finding the Fourth Proportional to 687.56, 1,031.03 and 218.91

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Solution

The fourth proportional to 687.56, 1,031.03 and 218.91 is: 328.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.56 : 1,031.03 = 218.91 : x
  2. Step 2: Convert to fraction form
    687.56/1,031.03 = 218.91/x
  3. Step 3: Cross multiply
    687.56x = 1,031.03 × 218.91
  4. Step 4: Simplify right side
    687.56x = 225,701.68
  5. Step 5: Solve for x
    x = 225,701.68/687.56
  6. Step 6: Final answer
    x = 328.27

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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.