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Finding the Fourth Proportional to 429.30, 643.86 and 140.58

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Solution

The fourth proportional to 429.30, 643.86 and 140.58 is: 210.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    429.30 : 643.86 = 140.58 : x
  2. Step 2: Convert to fraction form
    429.30/643.86 = 140.58/x
  3. Step 3: Cross multiply
    429.30x = 643.86 × 140.58
  4. Step 4: Simplify right side
    429.30x = 90,513.84
  5. Step 5: Solve for x
    x = 90,513.84/429.30
  6. Step 6: Final answer
    x = 210.84

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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.