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Finding the Fourth Proportional to 690.31, 1,035.87 and 257.77

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Solution

The fourth proportional to 690.31, 1,035.87 and 257.77 is: 386.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    690.31 : 1,035.87 = 257.77 : x
  2. Step 2: Convert to fraction form
    690.31/1,035.87 = 257.77/x
  3. Step 3: Cross multiply
    690.31x = 1,035.87 × 257.77
  4. Step 4: Simplify right side
    690.31x = 267,016.21
  5. Step 5: Solve for x
    x = 267,016.21/690.31
  6. Step 6: Final answer
    x = 386.81

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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.