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Finding the Fourth Proportional to 80.40, 111.08 and 64.15

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Solution

The fourth proportional to 80.40, 111.08 and 64.15 is: 88.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    80.40 : 111.08 = 64.15 : x
  2. Step 2: Convert to fraction form
    80.40/111.08 = 64.15/x
  3. Step 3: Cross multiply
    80.40x = 111.08 × 64.15
  4. Step 4: Simplify right side
    80.40x = 7,125.78
  5. Step 5: Solve for x
    x = 7,125.78/80.40
  6. Step 6: Final answer
    x = 88.63

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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.