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Finding the Fourth Proportional to 419.40, 628.74 and 145.35

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Solution

The fourth proportional to 419.40, 628.74 and 145.35 is: 217.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    419.40 : 628.74 = 145.35 : x
  2. Step 2: Convert to fraction form
    419.40/628.74 = 145.35/x
  3. Step 3: Cross multiply
    419.40x = 628.74 × 145.35
  4. Step 4: Simplify right side
    419.40x = 91,387.36
  5. Step 5: Solve for x
    x = 91,387.36/419.40
  6. Step 6: Final answer
    x = 217.90

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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.