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Finding the Fourth Proportional to 93.60, 128.95 and 78.79

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Solution

The fourth proportional to 93.60, 128.95 and 78.79 is: 108.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    93.60 : 128.95 = 78.79 : x
  2. Step 2: Convert to fraction form
    93.60/128.95 = 78.79/x
  3. Step 3: Cross multiply
    93.60x = 128.95 × 78.79
  4. Step 4: Simplify right side
    93.60x = 10,159.97
  5. Step 5: Solve for x
    x = 10,159.97/93.60
  6. Step 6: Final answer
    x = 108.55

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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.