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Finding the Fourth Proportional to 210.90, 315.81 and 129.63

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Solution

The fourth proportional to 210.90, 315.81 and 129.63 is: 194.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    210.90 : 315.81 = 129.63 : x
  2. Step 2: Convert to fraction form
    210.90/315.81 = 129.63/x
  3. Step 3: Cross multiply
    210.90x = 315.81 × 129.63
  4. Step 4: Simplify right side
    210.90x = 40,938.45
  5. Step 5: Solve for x
    x = 40,938.45/210.90
  6. Step 6: Final answer
    x = 194.11

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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.