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Finding the Fourth Proportional to 690.28, 1,035.66 and 257.68

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Solution

The fourth proportional to 690.28, 1,035.66 and 257.68 is: 386.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    690.28 : 1,035.66 = 257.68 : x
  2. Step 2: Convert to fraction form
    690.28/1,035.66 = 257.68/x
  3. Step 3: Cross multiply
    690.28x = 1,035.66 × 257.68
  4. Step 4: Simplify right side
    690.28x = 266,868.87
  5. Step 5: Solve for x
    x = 266,868.87/690.28
  6. Step 6: Final answer
    x = 386.61

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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.