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Finding the Fourth Proportional to 210.78, 315.92 and 89

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Solution

The fourth proportional to 210.78, 315.92 and 89 is: 133.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    210.78 : 315.92 = 89 : x
  2. Step 2: Convert to fraction form
    210.78/315.92 = 89/x
  3. Step 3: Cross multiply
    210.78x = 315.92 × 89
  4. Step 4: Simplify right side
    210.78x = 28,116.88
  5. Step 5: Solve for x
    x = 28,116.88/210.78
  6. Step 6: Final answer
    x = 133.39

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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.