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Finding the Fourth Proportional to 721.99, 1,076.18 and 643.49

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Solution

The fourth proportional to 721.99, 1,076.18 and 643.49 is: 959.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    721.99 : 1,076.18 = 643.49 : x
  2. Step 2: Convert to fraction form
    721.99/1,076.18 = 643.49/x
  3. Step 3: Cross multiply
    721.99x = 1,076.18 × 643.49
  4. Step 4: Simplify right side
    721.99x = 692,511.07
  5. Step 5: Solve for x
    x = 692,511.07/721.99
  6. Step 6: Final answer
    x = 959.17

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.