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Finding the Fourth Proportional to 664.40, 916.56 and 398.67

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Solution

The fourth proportional to 664.40, 916.56 and 398.67 is: 549.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    664.40 : 916.56 = 398.67 : x
  2. Step 2: Convert to fraction form
    664.40/916.56 = 398.67/x
  3. Step 3: Cross multiply
    664.40x = 916.56 × 398.67
  4. Step 4: Simplify right side
    664.40x = 365,404.98
  5. Step 5: Solve for x
    x = 365,404.98/664.40
  6. Step 6: Final answer
    x = 549.98

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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.