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Finding the Fourth Proportional to 716.70, 989.10 and 421.86

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Solution

The fourth proportional to 716.70, 989.10 and 421.86 is: 582.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    716.70 : 989.10 = 421.86 : x
  2. Step 2: Convert to fraction form
    716.70/989.10 = 421.86/x
  3. Step 3: Cross multiply
    716.70x = 989.10 × 421.86
  4. Step 4: Simplify right side
    716.70x = 417,261.73
  5. Step 5: Solve for x
    x = 417,261.73/716.70
  6. Step 6: Final answer
    x = 582.20

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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.