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Finding the Fourth Proportional to 515.45, 709.54 and 390.89

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Solution

The fourth proportional to 515.45, 709.54 and 390.89 is: 538.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    515.45 : 709.54 = 390.89 : x
  2. Step 2: Convert to fraction form
    515.45/709.54 = 390.89/x
  3. Step 3: Cross multiply
    515.45x = 709.54 × 390.89
  4. Step 4: Simplify right side
    515.45x = 277,347.57
  5. Step 5: Solve for x
    x = 277,347.57/515.45
  6. Step 6: Final answer
    x = 538.07

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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.