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Finding the Fourth Proportional to 429.19, 643.66 and 209.69

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Solution

The fourth proportional to 429.19, 643.66 and 209.69 is: 314.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    429.19 : 643.66 = 209.69 : x
  2. Step 2: Convert to fraction form
    429.19/643.66 = 209.69/x
  3. Step 3: Cross multiply
    429.19x = 643.66 × 209.69
  4. Step 4: Simplify right side
    429.19x = 134,970.67
  5. Step 5: Solve for x
    x = 134,970.67/429.19
  6. Step 6: Final answer
    x = 314.48

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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.