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Finding the Fourth Proportional to 420.75, 631.18 and 112.61

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Solution

The fourth proportional to 420.75, 631.18 and 112.61 is: 168.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.75 : 631.18 = 112.61 : x
  2. Step 2: Convert to fraction form
    420.75/631.18 = 112.61/x
  3. Step 3: Cross multiply
    420.75x = 631.18 × 112.61
  4. Step 4: Simplify right side
    420.75x = 71,075.04
  5. Step 5: Solve for x
    x = 71,075.04/420.75
  6. Step 6: Final answer
    x = 168.93

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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.