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Finding the Fourth Proportional to 93.39, 128.57 and 81.05

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Solution

The fourth proportional to 93.39, 128.57 and 81.05 is: 111.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    93.39 : 128.57 = 81.05 : x
  2. Step 2: Convert to fraction form
    93.39/128.57 = 81.05/x
  3. Step 3: Cross multiply
    93.39x = 128.57 × 81.05
  4. Step 4: Simplify right side
    93.39x = 10,419.55
  5. Step 5: Solve for x
    x = 10,419.55/93.39
  6. Step 6: Final answer
    x = 111.57

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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.