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Finding the Fourth Proportional to 971.20, 1,339.68 and 691

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Solution

The fourth proportional to 971.20, 1,339.68 and 691 is: 953.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    971.20 : 1,339.68 = 691 : x
  2. Step 2: Convert to fraction form
    971.20/1,339.68 = 691/x
  3. Step 3: Cross multiply
    971.20x = 1,339.68 × 691
  4. Step 4: Simplify right side
    971.20x = 925,718.88
  5. Step 5: Solve for x
    x = 925,718.88/971.20
  6. Step 6: Final answer
    x = 953.17

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.