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Finding the Fourth Proportional to 429.47, 643.29 and 405.51

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Solution

The fourth proportional to 429.47, 643.29 and 405.51 is: 607.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    429.47 : 643.29 = 405.51 : x
  2. Step 2: Convert to fraction form
    429.47/643.29 = 405.51/x
  3. Step 3: Cross multiply
    429.47x = 643.29 × 405.51
  4. Step 4: Simplify right side
    429.47x = 260,858.88
  5. Step 5: Solve for x
    x = 260,858.88/429.47
  6. Step 6: Final answer
    x = 607.40

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.