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Finding the Fourth Proportional to 420.59, 580.49 and 387.65

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Solution

The fourth proportional to 420.59, 580.49 and 387.65 is: 535.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.59 : 580.49 = 387.65 : x
  2. Step 2: Convert to fraction form
    420.59/580.49 = 387.65/x
  3. Step 3: Cross multiply
    420.59x = 580.49 × 387.65
  4. Step 4: Simplify right side
    420.59x = 225,022.11
  5. Step 5: Solve for x
    x = 225,022.11/420.59
  6. Step 6: Final answer
    x = 535.02

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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.