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Finding the Fourth Proportional to 429.72, 646.90 and 391.45

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Solution

The fourth proportional to 429.72, 646.90 and 391.45 is: 589.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    429.72 : 646.90 = 391.45 : x
  2. Step 2: Convert to fraction form
    429.72/646.90 = 391.45/x
  3. Step 3: Cross multiply
    429.72x = 646.90 × 391.45
  4. Step 4: Simplify right side
    429.72x = 253,223.81
  5. Step 5: Solve for x
    x = 253,223.81/429.72
  6. Step 6: Final answer
    x = 589.28

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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.