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Finding the Fourth Proportional to 769.61, 1,062.08 and 420.30

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Solution

The fourth proportional to 769.61, 1,062.08 and 420.30 is: 580.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    769.61 : 1,062.08 = 420.30 : x
  2. Step 2: Convert to fraction form
    769.61/1,062.08 = 420.30/x
  3. Step 3: Cross multiply
    769.61x = 1,062.08 × 420.30
  4. Step 4: Simplify right side
    769.61x = 446,390.12
  5. Step 5: Solve for x
    x = 446,390.12/769.61
  6. Step 6: Final answer
    x = 580.02

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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.