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Finding the Fourth Proportional to 769.41, 1,061.79 and 420.12

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Solution

The fourth proportional to 769.41, 1,061.79 and 420.12 is: 579.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    769.41 : 1,061.79 = 420.12 : x
  2. Step 2: Convert to fraction form
    769.41/1,061.79 = 420.12/x
  3. Step 3: Cross multiply
    769.41x = 1,061.79 × 420.12
  4. Step 4: Simplify right side
    769.41x = 446,079.21
  5. Step 5: Solve for x
    x = 446,079.21/769.41
  6. Step 6: Final answer
    x = 579.77

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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.