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Finding the Fourth Proportional to 420.99, 580.86 and 255.21

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Solution

The fourth proportional to 420.99, 580.86 and 255.21 is: 352.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.99 : 580.86 = 255.21 : x
  2. Step 2: Convert to fraction form
    420.99/580.86 = 255.21/x
  3. Step 3: Cross multiply
    420.99x = 580.86 × 255.21
  4. Step 4: Simplify right side
    420.99x = 148,241.28
  5. Step 5: Solve for x
    x = 148,241.28/420.99
  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.