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Finding the Fourth Proportional to 913.98, 1,369.40 and 639.57

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Solution

The fourth proportional to 913.98, 1,369.40 and 639.57 is: 958.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    913.98 : 1,369.40 = 639.57 : x
  2. Step 2: Convert to fraction form
    913.98/1,369.40 = 639.57/x
  3. Step 3: Cross multiply
    913.98x = 1,369.40 × 639.57
  4. Step 4: Simplify right side
    913.98x = 875,823.96
  5. Step 5: Solve for x
    x = 875,823.96/913.98
  6. Step 6: Final answer
    x = 958.25

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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.