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Finding the Fourth Proportional to 80.64, 111.28 and 64.38

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Solution

The fourth proportional to 80.64, 111.28 and 64.38 is: 88.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    80.64 : 111.28 = 64.38 : x
  2. Step 2: Convert to fraction form
    80.64/111.28 = 64.38/x
  3. Step 3: Cross multiply
    80.64x = 111.28 × 64.38
  4. Step 4: Simplify right side
    80.64x = 7,164.21
  5. Step 5: Solve for x
    x = 7,164.21/80.64
  6. Step 6: Final answer
    x = 88.84

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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.