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Finding the Fourth Proportional to 85, 117.36 and 64.30

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Solution

The fourth proportional to 85, 117.36 and 64.30 is: 88.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    85 : 117.36 = 64.30 : x
  2. Step 2: Convert to fraction form
    85/117.36 = 64.30/x
  3. Step 3: Cross multiply
    85x = 117.36 × 64.30
  4. Step 4: Simplify right side
    85x = 7,546.25
  5. Step 5: Solve for x
    x = 7,546.25/85
  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.