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Finding the Fourth Proportional to 429.15, 643.08 and 212.46

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Solution

The fourth proportional to 429.15, 643.08 and 212.46 is: 318.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    429.15 : 643.08 = 212.46 : x
  2. Step 2: Convert to fraction form
    429.15/643.08 = 212.46/x
  3. Step 3: Cross multiply
    429.15x = 643.08 × 212.46
  4. Step 4: Simplify right side
    429.15x = 136,628.78
  5. Step 5: Solve for x
    x = 136,628.78/429.15
  6. Step 6: Final answer
    x = 318.37

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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.