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Finding the Fourth Proportional to 419.81, 629.91 and 257.40

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Solution

The fourth proportional to 419.81, 629.91 and 257.40 is: 386.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    419.81 : 629.91 = 257.40 : x
  2. Step 2: Convert to fraction form
    419.81/629.91 = 257.40/x
  3. Step 3: Cross multiply
    419.81x = 629.91 × 257.40
  4. Step 4: Simplify right side
    419.81x = 162,138.83
  5. Step 5: Solve for x
    x = 162,138.83/419.81
  6. Step 6: Final answer
    x = 386.22

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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.