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Finding the Fourth Proportional to 319.20, 478.59 and 99.75

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Solution

The fourth proportional to 319.20, 478.59 and 99.75 is: 149.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    319.20 : 478.59 = 99.75 : x
  2. Step 2: Convert to fraction form
    319.20/478.59 = 99.75/x
  3. Step 3: Cross multiply
    319.20x = 478.59 × 99.75
  4. Step 4: Simplify right side
    319.20x = 47,739.05
  5. Step 5: Solve for x
    x = 47,739.05/319.20
  6. Step 6: Final answer
    x = 149.56

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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.