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Finding the Fourth Proportional to 128.45, 192.33 and 87.81

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Solution

The fourth proportional to 128.45, 192.33 and 87.81 is: 131.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.45 : 192.33 = 87.81 : x
  2. Step 2: Convert to fraction form
    128.45/192.33 = 87.81/x
  3. Step 3: Cross multiply
    128.45x = 192.33 × 87.81
  4. Step 4: Simplify right side
    128.45x = 16,888.50
  5. Step 5: Solve for x
    x = 16,888.50/128.45
  6. Step 6: Final answer
    x = 131.48

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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.