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Finding the Fourth Proportional to 76.32, 105.54 and 64.20

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Solution

The fourth proportional to 76.32, 105.54 and 64.20 is: 88.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    76.32 : 105.54 = 64.20 : x
  2. Step 2: Convert to fraction form
    76.32/105.54 = 64.20/x
  3. Step 3: Cross multiply
    76.32x = 105.54 × 64.20
  4. Step 4: Simplify right side
    76.32x = 6,775.67
  5. Step 5: Solve for x
    x = 6,775.67/76.32
  6. Step 6: Final answer
    x = 88.78

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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.