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Finding the Fourth Proportional to 78.11, 118.15 and 77.58

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Solution

The fourth proportional to 78.11, 118.15 and 77.58 is: 117.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.11 : 118.15 = 77.58 : x
  2. Step 2: Convert to fraction form
    78.11/118.15 = 77.58/x
  3. Step 3: Cross multiply
    78.11x = 118.15 × 77.58
  4. Step 4: Simplify right side
    78.11x = 9,166.08
  5. Step 5: Solve for x
    x = 9,166.08/78.11
  6. Step 6: Final answer
    x = 117.35

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.