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Finding the Fourth Proportional to 149.78, 206.86 and 100.70

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Solution

The fourth proportional to 149.78, 206.86 and 100.70 is: 139.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    149.78 : 206.86 = 100.70 : x
  2. Step 2: Convert to fraction form
    149.78/206.86 = 100.70/x
  3. Step 3: Cross multiply
    149.78x = 206.86 × 100.70
  4. Step 4: Simplify right side
    149.78x = 20,830.80
  5. Step 5: Solve for x
    x = 20,830.80/149.78
  6. Step 6: Final answer
    x = 139.08

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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.