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Finding the Fourth Proportional to 93.31, 128.79 and 65.65

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Solution

The fourth proportional to 93.31, 128.79 and 65.65 is: 90.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    93.31 : 128.79 = 65.65 : x
  2. Step 2: Convert to fraction form
    93.31/128.79 = 65.65/x
  3. Step 3: Cross multiply
    93.31x = 128.79 × 65.65
  4. Step 4: Simplify right side
    93.31x = 8,455.06
  5. Step 5: Solve for x
    x = 8,455.06/93.31
  6. Step 6: Final answer
    x = 90.61

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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.