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Finding the Fourth Proportional to 1,215.17, 1,677 and 691.20

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Solution

The fourth proportional to 1,215.17, 1,677 and 691.20 is: 953.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,215.17 : 1,677 = 691.20 : x
  2. Step 2: Convert to fraction form
    1,215.17/1,677 = 691.20/x
  3. Step 3: Cross multiply
    1,215.17x = 1,677 × 691.20
  4. Step 4: Simplify right side
    1,215.17x = 1,159,142.40
  5. Step 5: Solve for x
    x = 1,159,142.40/1,215.17
  6. Step 6: Final answer
    x = 953.90

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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.