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Finding the Fourth Proportional to 209.70, 314.30 and 87.90

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Solution

The fourth proportional to 209.70, 314.30 and 87.90 is: 131.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    209.70 : 314.30 = 87.90 : x
  2. Step 2: Convert to fraction form
    209.70/314.30 = 87.90/x
  3. Step 3: Cross multiply
    209.70x = 314.30 × 87.90
  4. Step 4: Simplify right side
    209.70x = 27,626.53
  5. Step 5: Solve for x
    x = 27,626.53/209.70
  6. Step 6: Final answer
    x = 131.74

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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.