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Finding the Fourth Proportional to 120.78, 181.20 and 56.64

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Solution

The fourth proportional to 120.78, 181.20 and 56.64 is: 84.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    120.78 : 181.20 = 56.64 : x
  2. Step 2: Convert to fraction form
    120.78/181.20 = 56.64/x
  3. Step 3: Cross multiply
    120.78x = 181.20 × 56.64
  4. Step 4: Simplify right side
    120.78x = 10,263.17
  5. Step 5: Solve for x
    x = 10,263.17/120.78
  6. Step 6: Final answer
    x = 84.97

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.