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Finding the Fourth Proportional to 70.19, 96.86 and 66.78

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Solution

The fourth proportional to 70.19, 96.86 and 66.78 is: 92.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    70.19 : 96.86 = 66.78 : x
  2. Step 2: Convert to fraction form
    70.19/96.86 = 66.78/x
  3. Step 3: Cross multiply
    70.19x = 96.86 × 66.78
  4. Step 4: Simplify right side
    70.19x = 6,468.31
  5. Step 5: Solve for x
    x = 6,468.31/70.19
  6. Step 6: Final answer
    x = 92.15

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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.