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Finding the Fourth Proportional to 690.56, 1,036.80 and 636.80

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Solution

The fourth proportional to 690.56, 1,036.80 and 636.80 is: 956.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    690.56 : 1,036.80 = 636.80 : x
  2. Step 2: Convert to fraction form
    690.56/1,036.80 = 636.80/x
  3. Step 3: Cross multiply
    690.56x = 1,036.80 × 636.80
  4. Step 4: Simplify right side
    690.56x = 660,234.24
  5. Step 5: Solve for x
    x = 660,234.24/690.56
  6. Step 6: Final answer
    x = 956.09

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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.