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Finding the Fourth Proportional to 326.40, 489.36 and 172.20

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Solution

The fourth proportional to 326.40, 489.36 and 172.20 is: 258.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    326.40 : 489.36 = 172.20 : x
  2. Step 2: Convert to fraction form
    326.40/489.36 = 172.20/x
  3. Step 3: Cross multiply
    326.40x = 489.36 × 172.20
  4. Step 4: Simplify right side
    326.40x = 84,267.79
  5. Step 5: Solve for x
    x = 84,267.79/326.40
  6. Step 6: Final answer
    x = 258.17

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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.