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Finding the Fourth Proportional to 690.69, 1,035.90 and 257.88

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Solution

The fourth proportional to 690.69, 1,035.90 and 257.88 is: 386.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    690.69 : 1,035.90 = 257.88 : x
  2. Step 2: Convert to fraction form
    690.69/1,035.90 = 257.88/x
  3. Step 3: Cross multiply
    690.69x = 1,035.90 × 257.88
  4. Step 4: Simplify right side
    690.69x = 267,137.89
  5. Step 5: Solve for x
    x = 267,137.89/690.69
  6. Step 6: Final answer
    x = 386.77

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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.