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Finding the Fourth Proportional to 78.98, 109.14 and 69.80

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Solution

The fourth proportional to 78.98, 109.14 and 69.80 is: 96.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.98 : 109.14 = 69.80 : x
  2. Step 2: Convert to fraction form
    78.98/109.14 = 69.80/x
  3. Step 3: Cross multiply
    78.98x = 109.14 × 69.80
  4. Step 4: Simplify right side
    78.98x = 7,617.97
  5. Step 5: Solve for x
    x = 7,617.97/78.98
  6. Step 6: Final answer
    x = 96.45

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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.