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Finding the Fourth Proportional to 687.35, 1,031.40 and 456.35

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Solution

The fourth proportional to 687.35, 1,031.40 and 456.35 is: 684.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.35 : 1,031.40 = 456.35 : x
  2. Step 2: Convert to fraction form
    687.35/1,031.40 = 456.35/x
  3. Step 3: Cross multiply
    687.35x = 1,031.40 × 456.35
  4. Step 4: Simplify right side
    687.35x = 470,680.03
  5. Step 5: Solve for x
    x = 470,680.03/687.35
  6. Step 6: Final answer
    x = 684.77

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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.