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Finding the Fourth Proportional to 419.11, 628.80 and 145.20

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Solution

The fourth proportional to 419.11, 628.80 and 145.20 is: 217.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    419.11 : 628.80 = 145.20 : x
  2. Step 2: Convert to fraction form
    419.11/628.80 = 145.20/x
  3. Step 3: Cross multiply
    419.11x = 628.80 × 145.20
  4. Step 4: Simplify right side
    419.11x = 91,301.76
  5. Step 5: Solve for x
    x = 91,301.76/419.11
  6. Step 6: Final answer
    x = 217.85

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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.