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Finding the Fourth Proportional to 820.47, 1,230.70 and 765.11

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Solution

The fourth proportional to 820.47, 1,230.70 and 765.11 is: 1,147.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    820.47 : 1,230.70 = 765.11 : x
  2. Step 2: Convert to fraction form
    820.47/1,230.70 = 765.11/x
  3. Step 3: Cross multiply
    820.47x = 1,230.70 × 765.11
  4. Step 4: Simplify right side
    820.47x = 941,618.82
  5. Step 5: Solve for x
    x = 941,618.82/820.47
  6. Step 6: Final answer
    x = 1,147.66

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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.