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Finding the Fourth Proportional to 93.42, 128.79 and 77.88

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Solution

The fourth proportional to 93.42, 128.79 and 77.88 is: 107.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    93.42 : 128.79 = 77.88 : x
  2. Step 2: Convert to fraction form
    93.42/128.79 = 77.88/x
  3. Step 3: Cross multiply
    93.42x = 128.79 × 77.88
  4. Step 4: Simplify right side
    93.42x = 10,030.17
  5. Step 5: Solve for x
    x = 10,030.17/93.42
  6. Step 6: Final answer
    x = 107.37

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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.