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Finding the Fourth Proportional to 420.74, 580.65 and 387.26

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Solution

The fourth proportional to 420.74, 580.65 and 387.26 is: 534.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.74 : 580.65 = 387.26 : x
  2. Step 2: Convert to fraction form
    420.74/580.65 = 387.26/x
  3. Step 3: Cross multiply
    420.74x = 580.65 × 387.26
  4. Step 4: Simplify right side
    420.74x = 224,862.52
  5. Step 5: Solve for x
    x = 224,862.52/420.74
  6. Step 6: Final answer
    x = 534.45

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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.