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Finding the Fourth Proportional to 456.49, 685.64 and 391.47

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Solution

The fourth proportional to 456.49, 685.64 and 391.47 is: 587.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    456.49 : 685.64 = 391.47 : x
  2. Step 2: Convert to fraction form
    456.49/685.64 = 391.47/x
  3. Step 3: Cross multiply
    456.49x = 685.64 × 391.47
  4. Step 4: Simplify right side
    456.49x = 268,407.49
  5. Step 5: Solve for x
    x = 268,407.49/456.49
  6. Step 6: Final answer
    x = 587.98

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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.