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Finding the Fourth Proportional to 687.69, 1,031.54 and 415.53

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Solution

The fourth proportional to 687.69, 1,031.54 and 415.53 is: 623.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.69 : 1,031.54 = 415.53 : x
  2. Step 2: Convert to fraction form
    687.69/1,031.54 = 415.53/x
  3. Step 3: Cross multiply
    687.69x = 1,031.54 × 415.53
  4. Step 4: Simplify right side
    687.69x = 428,633.74
  5. Step 5: Solve for x
    x = 428,633.74/687.69
  6. Step 6: Final answer
    x = 623.30

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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.