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Finding the Fourth Proportional to 319.80, 478.79 and 217.28

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Solution

The fourth proportional to 319.80, 478.79 and 217.28 is: 325.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    319.80 : 478.79 = 217.28 : x
  2. Step 2: Convert to fraction form
    319.80/478.79 = 217.28/x
  3. Step 3: Cross multiply
    319.80x = 478.79 × 217.28
  4. Step 4: Simplify right side
    319.80x = 104,031.81
  5. Step 5: Solve for x
    x = 104,031.81/319.80
  6. Step 6: Final answer
    x = 325.30

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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.