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Finding the Fourth Proportional to 645.57, 891.41 and 515.16

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Solution

The fourth proportional to 645.57, 891.41 and 515.16 is: 711.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    645.57 : 891.41 = 515.16 : x
  2. Step 2: Convert to fraction form
    645.57/891.41 = 515.16/x
  3. Step 3: Cross multiply
    645.57x = 891.41 × 515.16
  4. Step 4: Simplify right side
    645.57x = 459,216.20
  5. Step 5: Solve for x
    x = 459,216.20/645.57
  6. Step 6: Final answer
    x = 711.33

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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.