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Finding the Fourth Proportional to 429.60, 644.40 and 409.80

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Solution

The fourth proportional to 429.60, 644.40 and 409.80 is: 614.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    429.60 : 644.40 = 409.80 : x
  2. Step 2: Convert to fraction form
    429.60/644.40 = 409.80/x
  3. Step 3: Cross multiply
    429.60x = 644.40 × 409.80
  4. Step 4: Simplify right side
    429.60x = 264,075.12
  5. Step 5: Solve for x
    x = 264,075.12/429.60
  6. Step 6: Final answer
    x = 614.70

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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.