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Finding the Fourth Proportional to 128.58, 192.86 and 89.51

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Solution

The fourth proportional to 128.58, 192.86 and 89.51 is: 134.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.58 : 192.86 = 89.51 : x
  2. Step 2: Convert to fraction form
    128.58/192.86 = 89.51/x
  3. Step 3: Cross multiply
    128.58x = 192.86 × 89.51
  4. Step 4: Simplify right side
    128.58x = 17,262.90
  5. Step 5: Solve for x
    x = 17,262.90/128.58
  6. Step 6: Final answer
    x = 134.26

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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.