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Finding the Fourth Proportional to 128.85, 177.84 and 117.92

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Solution

The fourth proportional to 128.85, 177.84 and 117.92 is: 162.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.85 : 177.84 = 117.92 : x
  2. Step 2: Convert to fraction form
    128.85/177.84 = 117.92/x
  3. Step 3: Cross multiply
    128.85x = 177.84 × 117.92
  4. Step 4: Simplify right side
    128.85x = 20,970.23
  5. Step 5: Solve for x
    x = 20,970.23/128.85
  6. Step 6: Final answer
    x = 162.74

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.