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Finding the Fourth Proportional to 84.84, 126.62 and 78.90

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Solution

The fourth proportional to 84.84, 126.62 and 78.90 is: 117.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    84.84 : 126.62 = 78.90 : x
  2. Step 2: Convert to fraction form
    84.84/126.62 = 78.90/x
  3. Step 3: Cross multiply
    84.84x = 126.62 × 78.90
  4. Step 4: Simplify right side
    84.84x = 9,989.92
  5. Step 5: Solve for x
    x = 9,989.92/84.84
  6. Step 6: Final answer
    x = 117.75

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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.