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Finding the Fourth Proportional to 213.10, 318.90 and 139.93

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Solution

The fourth proportional to 213.10, 318.90 and 139.93 is: 209.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    213.10 : 318.90 = 139.93 : x
  2. Step 2: Convert to fraction form
    213.10/318.90 = 139.93/x
  3. Step 3: Cross multiply
    213.10x = 318.90 × 139.93
  4. Step 4: Simplify right side
    213.10x = 44,623.68
  5. Step 5: Solve for x
    x = 44,623.68/213.10
  6. Step 6: Final answer
    x = 209.40

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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.