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Finding the Fourth Proportional to 687.90, 1,031.63 and 225.60

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Solution

The fourth proportional to 687.90, 1,031.63 and 225.60 is: 338.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.90 : 1,031.63 = 225.60 : x
  2. Step 2: Convert to fraction form
    687.90/1,031.63 = 225.60/x
  3. Step 3: Cross multiply
    687.90x = 1,031.63 × 225.60
  4. Step 4: Simplify right side
    687.90x = 232,732.02
  5. Step 5: Solve for x
    x = 232,732.02/687.90
  6. Step 6: Final answer
    x = 338.32

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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.