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Finding the Fourth Proportional to 78.55, 117.31 and 67.16

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Solution

The fourth proportional to 78.55, 117.31 and 67.16 is: 100.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.55 : 117.31 = 67.16 : x
  2. Step 2: Convert to fraction form
    78.55/117.31 = 67.16/x
  3. Step 3: Cross multiply
    78.55x = 117.31 × 67.16
  4. Step 4: Simplify right side
    78.55x = 7,878.54
  5. Step 5: Solve for x
    x = 7,878.54/78.55
  6. Step 6: Final answer
    x = 100.30

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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.