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Finding the Fourth Proportional to 85.36, 126.98 and 78.48

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Solution

The fourth proportional to 85.36, 126.98 and 78.48 is: 116.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.36 : 126.98 = 78.48 : x
  2. Step 2: Convert to fraction form
    85.36/126.98 = 78.48/x
  3. Step 3: Cross multiply
    85.36x = 126.98 × 78.48
  4. Step 4: Simplify right side
    85.36x = 9,965.39
  5. Step 5: Solve for x
    x = 9,965.39/85.36
  6. Step 6: Final answer
    x = 116.75

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.