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Finding the Fourth Proportional to 429.02, 643.70 and 209.74

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Solution

The fourth proportional to 429.02, 643.70 and 209.74 is: 314.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    429.02 : 643.70 = 209.74 : x
  2. Step 2: Convert to fraction form
    429.02/643.70 = 209.74/x
  3. Step 3: Cross multiply
    429.02x = 643.70 × 209.74
  4. Step 4: Simplify right side
    429.02x = 135,009.64
  5. Step 5: Solve for x
    x = 135,009.64/429.02
  6. Step 6: Final answer
    x = 314.69

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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.