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Finding the Fourth Proportional to 690.46, 1,035.99 and 638.21

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Solution

The fourth proportional to 690.46, 1,035.99 and 638.21 is: 957.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    690.46 : 1,035.99 = 638.21 : x
  2. Step 2: Convert to fraction form
    690.46/1,035.99 = 638.21/x
  3. Step 3: Cross multiply
    690.46x = 1,035.99 × 638.21
  4. Step 4: Simplify right side
    690.46x = 661,181.77
  5. Step 5: Solve for x
    x = 661,181.77/690.46
  6. Step 6: Final answer
    x = 957.60

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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.