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Finding the Fourth Proportional to 93.31, 128.74 and 64.20

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Solution

The fourth proportional to 93.31, 128.74 and 64.20 is: 88.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    93.31 : 128.74 = 64.20 : x
  2. Step 2: Convert to fraction form
    93.31/128.74 = 64.20/x
  3. Step 3: Cross multiply
    93.31x = 128.74 × 64.20
  4. Step 4: Simplify right side
    93.31x = 8,265.11
  5. Step 5: Solve for x
    x = 8,265.11/93.31
  6. Step 6: Final answer
    x = 88.58

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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.