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Finding the Fourth Proportional to 420.93, 631.41 and 112.78

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Solution

The fourth proportional to 420.93, 631.41 and 112.78 is: 169.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.93 : 631.41 = 112.78 : x
  2. Step 2: Convert to fraction form
    420.93/631.41 = 112.78/x
  3. Step 3: Cross multiply
    420.93x = 631.41 × 112.78
  4. Step 4: Simplify right side
    420.93x = 71,209.86
  5. Step 5: Solve for x
    x = 71,209.86/420.93
  6. Step 6: Final answer
    x = 169.17

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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.