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Finding the Fourth Proportional to 713.72, 990.16 and 687.80

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Solution

The fourth proportional to 713.72, 990.16 and 687.80 is: 954.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    713.72 : 990.16 = 687.80 : x
  2. Step 2: Convert to fraction form
    713.72/990.16 = 687.80/x
  3. Step 3: Cross multiply
    713.72x = 990.16 × 687.80
  4. Step 4: Simplify right side
    713.72x = 681,032.05
  5. Step 5: Solve for x
    x = 681,032.05/713.72
  6. Step 6: Final answer
    x = 954.20

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.