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Finding the Fourth Proportional to 515.48, 712.30 and 390.94

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Solution

The fourth proportional to 515.48, 712.30 and 390.94 is: 540.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    515.48 : 712.30 = 390.94 : x
  2. Step 2: Convert to fraction form
    515.48/712.30 = 390.94/x
  3. Step 3: Cross multiply
    515.48x = 712.30 × 390.94
  4. Step 4: Simplify right side
    515.48x = 278,466.56
  5. Step 5: Solve for x
    x = 278,466.56/515.48
  6. Step 6: Final answer
    x = 540.21

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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.