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Finding the Fourth Proportional to 93.78, 139.80 and 91.80

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Solution

The fourth proportional to 93.78, 139.80 and 91.80 is: 136.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    93.78 : 139.80 = 91.80 : x
  2. Step 2: Convert to fraction form
    93.78/139.80 = 91.80/x
  3. Step 3: Cross multiply
    93.78x = 139.80 × 91.80
  4. Step 4: Simplify right side
    93.78x = 12,833.64
  5. Step 5: Solve for x
    x = 12,833.64/93.78
  6. Step 6: Final answer
    x = 136.85

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.