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Finding the Fourth Proportional to 80.64, 111.30 and 61.28

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Solution

The fourth proportional to 80.64, 111.30 and 61.28 is: 84.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    80.64 : 111.30 = 61.28 : x
  2. Step 2: Convert to fraction form
    80.64/111.30 = 61.28/x
  3. Step 3: Cross multiply
    80.64x = 111.30 × 61.28
  4. Step 4: Simplify right side
    80.64x = 6,820.46
  5. Step 5: Solve for x
    x = 6,820.46/80.64
  6. Step 6: Final answer
    x = 84.58

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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.