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Finding the Fourth Proportional to 429.10, 643.84 and 212.64

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Solution

The fourth proportional to 429.10, 643.84 and 212.64 is: 319.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    429.10 : 643.84 = 212.64 : x
  2. Step 2: Convert to fraction form
    429.10/643.84 = 212.64/x
  3. Step 3: Cross multiply
    429.10x = 643.84 × 212.64
  4. Step 4: Simplify right side
    429.10x = 136,906.14
  5. Step 5: Solve for x
    x = 136,906.14/429.10
  6. Step 6: Final answer
    x = 319.05

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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.