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Finding the Fourth Proportional to 419.80, 629.98 and 311.90

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Solution

The fourth proportional to 419.80, 629.98 and 311.90 is: 468.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    419.80 : 629.98 = 311.90 : x
  2. Step 2: Convert to fraction form
    419.80/629.98 = 311.90/x
  3. Step 3: Cross multiply
    419.80x = 629.98 × 311.90
  4. Step 4: Simplify right side
    419.80x = 196,490.76
  5. Step 5: Solve for x
    x = 196,490.76/419.80
  6. Step 6: Final answer
    x = 468.06

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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.