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Finding the Fourth Proportional to 93.78, 129.36 and 66.18

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Solution

The fourth proportional to 93.78, 129.36 and 66.18 is: 91.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    93.78 : 129.36 = 66.18 : x
  2. Step 2: Convert to fraction form
    93.78/129.36 = 66.18/x
  3. Step 3: Cross multiply
    93.78x = 129.36 × 66.18
  4. Step 4: Simplify right side
    93.78x = 8,561.04
  5. Step 5: Solve for x
    x = 8,561.04/93.78
  6. Step 6: Final answer
    x = 91.29

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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.