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Finding the Fourth Proportional to 429.79, 647.21 and 308.90

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Solution

The fourth proportional to 429.79, 647.21 and 308.90 is: 465.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    429.79 : 647.21 = 308.90 : x
  2. Step 2: Convert to fraction form
    429.79/647.21 = 308.90/x
  3. Step 3: Cross multiply
    429.79x = 647.21 × 308.90
  4. Step 4: Simplify right side
    429.79x = 199,918.39
  5. Step 5: Solve for x
    x = 199,918.39/429.79
  6. Step 6: Final answer
    x = 465.15

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.