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Finding the Fourth Proportional to 393.99, 542.76 and 320.78

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Solution

The fourth proportional to 393.99, 542.76 and 320.78 is: 441.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    393.99 : 542.76 = 320.78 : x
  2. Step 2: Convert to fraction form
    393.99/542.76 = 320.78/x
  3. Step 3: Cross multiply
    393.99x = 542.76 × 320.78
  4. Step 4: Simplify right side
    393.99x = 174,106.55
  5. Step 5: Solve for x
    x = 174,106.55/393.99
  6. Step 6: Final answer
    x = 441.91

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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.