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Finding the Fourth Proportional to 421.35, 631.55 and 189.90

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Solution

The fourth proportional to 421.35, 631.55 and 189.90 is: 284.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.35 : 631.55 = 189.90 : x
  2. Step 2: Convert to fraction form
    421.35/631.55 = 189.90/x
  3. Step 3: Cross multiply
    421.35x = 631.55 × 189.90
  4. Step 4: Simplify right side
    421.35x = 119,931.35
  5. Step 5: Solve for x
    x = 119,931.35/421.35
  6. Step 6: Final answer
    x = 284.64

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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.