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Finding the Fourth Proportional to 769.36, 1,061.72 and 420.08

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Solution

The fourth proportional to 769.36, 1,061.72 and 420.08 is: 579.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    769.36 : 1,061.72 = 420.08 : x
  2. Step 2: Convert to fraction form
    769.36/1,061.72 = 420.08/x
  3. Step 3: Cross multiply
    769.36x = 1,061.72 × 420.08
  4. Step 4: Simplify right side
    769.36x = 446,007.34
  5. Step 5: Solve for x
    x = 446,007.34/769.36
  6. Step 6: Final answer
    x = 579.71

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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.