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Finding the Fourth Proportional to 429.80, 644.70 and 309.20

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Solution

The fourth proportional to 429.80, 644.70 and 309.20 is: 463.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    429.80 : 644.70 = 309.20 : x
  2. Step 2: Convert to fraction form
    429.80/644.70 = 309.20/x
  3. Step 3: Cross multiply
    429.80x = 644.70 × 309.20
  4. Step 4: Simplify right side
    429.80x = 199,341.24
  5. Step 5: Solve for x
    x = 199,341.24/429.80
  6. Step 6: Final answer
    x = 463.80

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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.