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Finding the Fourth Proportional to 419.31, 629.12 and 145.40

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Solution

The fourth proportional to 419.31, 629.12 and 145.40 is: 218.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    419.31 : 629.12 = 145.40 : x
  2. Step 2: Convert to fraction form
    419.31/629.12 = 145.40/x
  3. Step 3: Cross multiply
    419.31x = 629.12 × 145.40
  4. Step 4: Simplify right side
    419.31x = 91,470.45
  5. Step 5: Solve for x
    x = 91,470.45/419.31
  6. Step 6: Final answer
    x = 218.14

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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.