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Finding the Fourth Proportional to 768.60, 1,151.55 and 421.56

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Solution

The fourth proportional to 768.60, 1,151.55 and 421.56 is: 631.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    768.60 : 1,151.55 = 421.56 : x
  2. Step 2: Convert to fraction form
    768.60/1,151.55 = 421.56/x
  3. Step 3: Cross multiply
    768.60x = 1,151.55 × 421.56
  4. Step 4: Simplify right side
    768.60x = 485,447.42
  5. Step 5: Solve for x
    x = 485,447.42/768.60
  6. Step 6: Final answer
    x = 631.60

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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.