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Finding the Fourth Proportional to 769.49, 1,061.89 and 420.18

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Solution

The fourth proportional to 769.49, 1,061.89 and 420.18 is: 579.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    769.49 : 1,061.89 = 420.18 : x
  2. Step 2: Convert to fraction form
    769.49/1,061.89 = 420.18/x
  3. Step 3: Cross multiply
    769.49x = 1,061.89 × 420.18
  4. Step 4: Simplify right side
    769.49x = 446,179.63
  5. Step 5: Solve for x
    x = 446,179.63/769.49
  6. Step 6: Final answer
    x = 579.84

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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.