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Finding the Fourth Proportional to 117.60, 176.40 and 81.15

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Solution

The fourth proportional to 117.60, 176.40 and 81.15 is: 121.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    117.60 : 176.40 = 81.15 : x
  2. Step 2: Convert to fraction form
    117.60/176.40 = 81.15/x
  3. Step 3: Cross multiply
    117.60x = 176.40 × 81.15
  4. Step 4: Simplify right side
    117.60x = 14,314.86
  5. Step 5: Solve for x
    x = 14,314.86/117.60
  6. Step 6: Final answer
    x = 121.73

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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.