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Finding the Fourth Proportional to 770.14, 1,062.81 and 420.85

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Solution

The fourth proportional to 770.14, 1,062.81 and 420.85 is: 580.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    770.14 : 1,062.81 = 420.85 : x
  2. Step 2: Convert to fraction form
    770.14/1,062.81 = 420.85/x
  3. Step 3: Cross multiply
    770.14x = 1,062.81 × 420.85
  4. Step 4: Simplify right side
    770.14x = 447,283.59
  5. Step 5: Solve for x
    x = 447,283.59/770.14
  6. Step 6: Final answer
    x = 580.78

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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.