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Finding the Fourth Proportional to 209.19, 313.78 and 100.90

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Solution

The fourth proportional to 209.19, 313.78 and 100.90 is: 151.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    209.19 : 313.78 = 100.90 : x
  2. Step 2: Convert to fraction form
    209.19/313.78 = 100.90/x
  3. Step 3: Cross multiply
    209.19x = 313.78 × 100.90
  4. Step 4: Simplify right side
    209.19x = 31,659.75
  5. Step 5: Solve for x
    x = 31,659.75/209.19
  6. Step 6: Final answer
    x = 151.35

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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.