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Finding the Fourth Proportional to 128.58, 192.96 and 70.86

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Solution

The fourth proportional to 128.58, 192.96 and 70.86 is: 106.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.58 : 192.96 = 70.86 : x
  2. Step 2: Convert to fraction form
    128.58/192.96 = 70.86/x
  3. Step 3: Cross multiply
    128.58x = 192.96 × 70.86
  4. Step 4: Simplify right side
    128.58x = 13,673.15
  5. Step 5: Solve for x
    x = 13,673.15/128.58
  6. Step 6: Final answer
    x = 106.34

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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.