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Finding the Fourth Proportional to 421.21, 631.29 and 189.77

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Solution

The fourth proportional to 421.21, 631.29 and 189.77 is: 284.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.21 : 631.29 = 189.77 : x
  2. Step 2: Convert to fraction form
    421.21/631.29 = 189.77/x
  3. Step 3: Cross multiply
    421.21x = 631.29 × 189.77
  4. Step 4: Simplify right side
    421.21x = 119,799.90
  5. Step 5: Solve for x
    x = 119,799.90/421.21
  6. Step 6: Final answer
    x = 284.42

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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.