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Finding the Fourth Proportional to 515.75, 711.19 and 390.00

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Solution

The fourth proportional to 515.75, 711.19 and 390.00 is: 537.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    515.75 : 711.19 = 390.00 : x
  2. Step 2: Convert to fraction form
    515.75/711.19 = 390.00/x
  3. Step 3: Cross multiply
    515.75x = 711.19 × 390.00
  4. Step 4: Simplify right side
    515.75x = 277,365.06
  5. Step 5: Solve for x
    x = 277,365.06/515.75
  6. Step 6: Final answer
    x = 537.79

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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.