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Finding the Fourth Proportional to 389.80, 538.70 and 319.75

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Solution

The fourth proportional to 389.80, 538.70 and 319.75 is: 441.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    389.80 : 538.70 = 319.75 : x
  2. Step 2: Convert to fraction form
    389.80/538.70 = 319.75/x
  3. Step 3: Cross multiply
    389.80x = 538.70 × 319.75
  4. Step 4: Simplify right side
    389.80x = 172,249.33
  5. Step 5: Solve for x
    x = 172,249.33/389.80
  6. Step 6: Final answer
    x = 441.89

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.