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Finding the Fourth Proportional to 664.20, 916.65 and 402.21

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Solution

The fourth proportional to 664.20, 916.65 and 402.21 is: 555.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    664.20 : 916.65 = 402.21 : x
  2. Step 2: Convert to fraction form
    664.20/916.65 = 402.21/x
  3. Step 3: Cross multiply
    664.20x = 916.65 × 402.21
  4. Step 4: Simplify right side
    664.20x = 368,685.80
  5. Step 5: Solve for x
    x = 368,685.80/664.20
  6. Step 6: Final answer
    x = 555.08

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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.