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Finding the Fourth Proportional to 690.10, 1,040.32 and 644.27

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Solution

The fourth proportional to 690.10, 1,040.32 and 644.27 is: 971.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    690.10 : 1,040.32 = 644.27 : x
  2. Step 2: Convert to fraction form
    690.10/1,040.32 = 644.27/x
  3. Step 3: Cross multiply
    690.10x = 1,040.32 × 644.27
  4. Step 4: Simplify right side
    690.10x = 670,243.75
  5. Step 5: Solve for x
    x = 670,243.75/690.10
  6. Step 6: Final answer
    x = 971.23

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.