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Finding the Fourth Proportional to 213.20, 317.92 and 172.40

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Solution

The fourth proportional to 213.20, 317.92 and 172.40 is: 257.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    213.20 : 317.92 = 172.40 : x
  2. Step 2: Convert to fraction form
    213.20/317.92 = 172.40/x
  3. Step 3: Cross multiply
    213.20x = 317.92 × 172.40
  4. Step 4: Simplify right side
    213.20x = 54,809.41
  5. Step 5: Solve for x
    x = 54,809.41/213.20
  6. Step 6: Final answer
    x = 257.08

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.