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Finding the Fourth Proportional to 93.78, 139.68 and 90.72

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Solution

The fourth proportional to 93.78, 139.68 and 90.72 is: 135.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    93.78 : 139.68 = 90.72 : x
  2. Step 2: Convert to fraction form
    93.78/139.68 = 90.72/x
  3. Step 3: Cross multiply
    93.78x = 139.68 × 90.72
  4. Step 4: Simplify right side
    93.78x = 12,671.77
  5. Step 5: Solve for x
    x = 12,671.77/93.78
  6. Step 6: Final answer
    x = 135.12

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