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Finding the Fourth Proportional to 80.64, 111.35 and 61.20

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Solution

The fourth proportional to 80.64, 111.35 and 61.20 is: 84.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    80.64 : 111.35 = 61.20 : x
  2. Step 2: Convert to fraction form
    80.64/111.35 = 61.20/x
  3. Step 3: Cross multiply
    80.64x = 111.35 × 61.20
  4. Step 4: Simplify right side
    80.64x = 6,814.31
  5. Step 5: Solve for x
    x = 6,814.31/80.64
  6. Step 6: Final answer
    x = 84.50

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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.