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Finding the Fourth Proportional to 664.58, 915.90 and 515

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Solution

The fourth proportional to 664.58, 915.90 and 515 is: 709.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    664.58 : 915.90 = 515 : x
  2. Step 2: Convert to fraction form
    664.58/915.90 = 515/x
  3. Step 3: Cross multiply
    664.58x = 915.90 × 515
  4. Step 4: Simplify right side
    664.58x = 471,688.50
  5. Step 5: Solve for x
    x = 471,688.50/664.58
  6. Step 6: Final answer
    x = 709.75

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.