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Finding the Fourth Proportional to 690.27, 1,036.31 and 639.24

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Solution

The fourth proportional to 690.27, 1,036.31 and 639.24 is: 959.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    690.27 : 1,036.31 = 639.24 : x
  2. Step 2: Convert to fraction form
    690.27/1,036.31 = 639.24/x
  3. Step 3: Cross multiply
    690.27x = 1,036.31 × 639.24
  4. Step 4: Simplify right side
    690.27x = 662,450.80
  5. Step 5: Solve for x
    x = 662,450.80/690.27
  6. Step 6: Final answer
    x = 959.70

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.