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Finding the Fourth Proportional to 390.64, 538.62 and 320.48

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Solution

The fourth proportional to 390.64, 538.62 and 320.48 is: 441.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.64 : 538.62 = 320.48 : x
  2. Step 2: Convert to fraction form
    390.64/538.62 = 320.48/x
  3. Step 3: Cross multiply
    390.64x = 538.62 × 320.48
  4. Step 4: Simplify right side
    390.64x = 172,616.94
  5. Step 5: Solve for x
    x = 172,616.94/390.64
  6. Step 6: Final answer
    x = 441.88

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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.