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Finding the Fourth Proportional to 78.70, 117.34 and 78.07

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Solution

The fourth proportional to 78.70, 117.34 and 78.07 is: 116.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.70 : 117.34 = 78.07 : x
  2. Step 2: Convert to fraction form
    78.70/117.34 = 78.07/x
  3. Step 3: Cross multiply
    78.70x = 117.34 × 78.07
  4. Step 4: Simplify right side
    78.70x = 9,160.73
  5. Step 5: Solve for x
    x = 9,160.73/78.70
  6. Step 6: Final answer
    x = 116.40

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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.