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Finding the Fourth Proportional to 93.39, 128.90 and 56.55

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Solution

The fourth proportional to 93.39, 128.90 and 56.55 is: 78.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    93.39 : 128.90 = 56.55 : x
  2. Step 2: Convert to fraction form
    93.39/128.90 = 56.55/x
  3. Step 3: Cross multiply
    93.39x = 128.90 × 56.55
  4. Step 4: Simplify right side
    93.39x = 7,289.01
  5. Step 5: Solve for x
    x = 7,289.01/93.39
  6. Step 6: Final answer
    x = 78.05

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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.