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Finding the Fourth Proportional to 210.69, 315.36 and 138.42

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Solution

The fourth proportional to 210.69, 315.36 and 138.42 is: 207.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    210.69 : 315.36 = 138.42 : x
  2. Step 2: Convert to fraction form
    210.69/315.36 = 138.42/x
  3. Step 3: Cross multiply
    210.69x = 315.36 × 138.42
  4. Step 4: Simplify right side
    210.69x = 43,652.13
  5. Step 5: Solve for x
    x = 43,652.13/210.69
  6. Step 6: Final answer
    x = 207.19

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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.