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Finding the Fourth Proportional to 139.78, 192.88 and 84.55

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Solution

The fourth proportional to 139.78, 192.88 and 84.55 is: 116.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.78 : 192.88 = 84.55 : x
  2. Step 2: Convert to fraction form
    139.78/192.88 = 84.55/x
  3. Step 3: Cross multiply
    139.78x = 192.88 × 84.55
  4. Step 4: Simplify right side
    139.78x = 16,307.58
  5. Step 5: Solve for x
    x = 16,307.58/139.78
  6. Step 6: Final answer
    x = 116.67

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.