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Finding the Fourth Proportional to 420.90, 580.90 and 255.14

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Solution

The fourth proportional to 420.90, 580.90 and 255.14 is: 352.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.90 : 580.90 = 255.14 : x
  2. Step 2: Convert to fraction form
    420.90/580.90 = 255.14/x
  3. Step 3: Cross multiply
    420.90x = 580.90 × 255.14
  4. Step 4: Simplify right side
    420.90x = 148,210.83
  5. Step 5: Solve for x
    x = 148,210.83/420.90
  6. Step 6: Final answer
    x = 352.13

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.