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Finding the Fourth Proportional to 93.12, 138.72 and 91.20

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Solution

The fourth proportional to 93.12, 138.72 and 91.20 is: 135.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    93.12 : 138.72 = 91.20 : x
  2. Step 2: Convert to fraction form
    93.12/138.72 = 91.20/x
  3. Step 3: Cross multiply
    93.12x = 138.72 × 91.20
  4. Step 4: Simplify right side
    93.12x = 12,651.26
  5. Step 5: Solve for x
    x = 12,651.26/93.12
  6. Step 6: Final answer
    x = 135.86

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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.