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Finding the Fourth Proportional to 421.82, 633.94 and 391.64

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Solution

The fourth proportional to 421.82, 633.94 and 391.64 is: 588.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.82 : 633.94 = 391.64 : x
  2. Step 2: Convert to fraction form
    421.82/633.94 = 391.64/x
  3. Step 3: Cross multiply
    421.82x = 633.94 × 391.64
  4. Step 4: Simplify right side
    421.82x = 248,276.26
  5. Step 5: Solve for x
    x = 248,276.26/421.82
  6. Step 6: Final answer
    x = 588.58

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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.