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Finding the Fourth Proportional to 515.57, 709.71 and 391.01

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Solution

The fourth proportional to 515.57, 709.71 and 391.01 is: 538.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    515.57 : 709.71 = 391.01 : x
  2. Step 2: Convert to fraction form
    515.57/709.71 = 391.01/x
  3. Step 3: Cross multiply
    515.57x = 709.71 × 391.01
  4. Step 4: Simplify right side
    515.57x = 277,503.71
  5. Step 5: Solve for x
    x = 277,503.71/515.57
  6. Step 6: Final answer
    x = 538.25

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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.