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Finding the Fourth Proportional to 515.84, 712.10 and 390.51

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Solution

The fourth proportional to 515.84, 712.10 and 390.51 is: 539.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    515.84 : 712.10 = 390.51 : x
  2. Step 2: Convert to fraction form
    515.84/712.10 = 390.51/x
  3. Step 3: Cross multiply
    515.84x = 712.10 × 390.51
  4. Step 4: Simplify right side
    515.84x = 278,083.15
  5. Step 5: Solve for x
    x = 278,083.15/515.84
  6. Step 6: Final answer
    x = 539.09

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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.