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Finding the Fourth Proportional to 128.79, 192.98 and 56.57

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Solution

The fourth proportional to 128.79, 192.98 and 56.57 is: 84.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.79 : 192.98 = 56.57 : x
  2. Step 2: Convert to fraction form
    128.79/192.98 = 56.57/x
  3. Step 3: Cross multiply
    128.79x = 192.98 × 56.57
  4. Step 4: Simplify right side
    128.79x = 10,916.06
  5. Step 5: Solve for x
    x = 10,916.06/128.79
  6. Step 6: Final answer
    x = 84.76

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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.