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Finding the Fourth Proportional to 716.72, 989.20 and 520.80

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Solution

The fourth proportional to 716.72, 989.20 and 520.80 is: 718.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    716.72 : 989.20 = 520.80 : x
  2. Step 2: Convert to fraction form
    716.72/989.20 = 520.80/x
  3. Step 3: Cross multiply
    716.72x = 989.20 × 520.80
  4. Step 4: Simplify right side
    716.72x = 515,175.36
  5. Step 5: Solve for x
    x = 515,175.36/716.72
  6. Step 6: Final answer
    x = 718.80

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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.