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Finding the Fourth Proportional to 721.50, 997.47 and 690.90

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Solution

The fourth proportional to 721.50, 997.47 and 690.90 is: 955.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    721.50 : 997.47 = 690.90 : x
  2. Step 2: Convert to fraction form
    721.50/997.47 = 690.90/x
  3. Step 3: Cross multiply
    721.50x = 997.47 × 690.90
  4. Step 4: Simplify right side
    721.50x = 689,152.02
  5. Step 5: Solve for x
    x = 689,152.02/721.50
  6. Step 6: Final answer
    x = 955.17

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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.