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Finding the Fourth Proportional to 486.70, 729.89 and 428.98

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Solution

The fourth proportional to 486.70, 729.89 and 428.98 is: 643.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    486.70 : 729.89 = 428.98 : x
  2. Step 2: Convert to fraction form
    486.70/729.89 = 428.98/x
  3. Step 3: Cross multiply
    486.70x = 729.89 × 428.98
  4. Step 4: Simplify right side
    486.70x = 313,108.21
  5. Step 5: Solve for x
    x = 313,108.21/486.70
  6. Step 6: Final answer
    x = 643.33

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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.