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Finding the Fourth Proportional to 390.76, 538.65 and 320.63

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Solution

The fourth proportional to 390.76, 538.65 and 320.63 is: 441.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.76 : 538.65 = 320.63 : x
  2. Step 2: Convert to fraction form
    390.76/538.65 = 320.63/x
  3. Step 3: Cross multiply
    390.76x = 538.65 × 320.63
  4. Step 4: Simplify right side
    390.76x = 172,704.66
  5. Step 5: Solve for x
    x = 172,704.66/390.76
  6. Step 6: Final answer
    x = 441.97

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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.