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Finding the Fourth Proportional to 92.65, 139.08 and 78.39

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Solution

The fourth proportional to 92.65, 139.08 and 78.39 is: 117.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    92.65 : 139.08 = 78.39 : x
  2. Step 2: Convert to fraction form
    92.65/139.08 = 78.39/x
  3. Step 3: Cross multiply
    92.65x = 139.08 × 78.39
  4. Step 4: Simplify right side
    92.65x = 10,901.79
  5. Step 5: Solve for x
    x = 10,901.79/92.65
  6. Step 6: Final answer
    x = 117.67

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.