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Finding the Fourth Proportional to 429.45, 643.96 and 212.77

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Solution

The fourth proportional to 429.45, 643.96 and 212.77 is: 319.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    429.45 : 643.96 = 212.77 : x
  2. Step 2: Convert to fraction form
    429.45/643.96 = 212.77/x
  3. Step 3: Cross multiply
    429.45x = 643.96 × 212.77
  4. Step 4: Simplify right side
    429.45x = 137,015.37
  5. Step 5: Solve for x
    x = 137,015.37/429.45
  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.