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Finding the Fourth Proportional to 716.39, 988.61 and 421.61

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Solution

The fourth proportional to 716.39, 988.61 and 421.61 is: 581.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    716.39 : 988.61 = 421.61 : x
  2. Step 2: Convert to fraction form
    716.39/988.61 = 421.61/x
  3. Step 3: Cross multiply
    716.39x = 988.61 × 421.61
  4. Step 4: Simplify right side
    716.39x = 416,807.86
  5. Step 5: Solve for x
    x = 416,807.86/716.39
  6. Step 6: Final answer
    x = 581.82

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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.