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Finding the Fourth Proportional to 128.38, 176.98 and 84.64

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Solution

The fourth proportional to 128.38, 176.98 and 84.64 is: 116.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.38 : 176.98 = 84.64 : x
  2. Step 2: Convert to fraction form
    128.38/176.98 = 84.64/x
  3. Step 3: Cross multiply
    128.38x = 176.98 × 84.64
  4. Step 4: Simplify right side
    128.38x = 14,980.24
  5. Step 5: Solve for x
    x = 14,980.24/128.38
  6. Step 6: Final answer
    x = 116.68

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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.