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Finding the Fourth Proportional to 399.58, 550.28 and 391.10

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Solution

The fourth proportional to 399.58, 550.28 and 391.10 is: 538.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    399.58 : 550.28 = 391.10 : x
  2. Step 2: Convert to fraction form
    399.58/550.28 = 391.10/x
  3. Step 3: Cross multiply
    399.58x = 550.28 × 391.10
  4. Step 4: Simplify right side
    399.58x = 215,214.51
  5. Step 5: Solve for x
    x = 215,214.51/399.58
  6. Step 6: Final answer
    x = 538.60

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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.