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Finding the Fourth Proportional to 770.20, 1,155.30 and 539.80

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Solution

The fourth proportional to 770.20, 1,155.30 and 539.80 is: 809.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    770.20 : 1,155.30 = 539.80 : x
  2. Step 2: Convert to fraction form
    770.20/1,155.30 = 539.80/x
  3. Step 3: Cross multiply
    770.20x = 1,155.30 × 539.80
  4. Step 4: Simplify right side
    770.20x = 623,630.94
  5. Step 5: Solve for x
    x = 623,630.94/770.20
  6. Step 6: Final answer
    x = 809.70

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.