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Finding the Fourth Proportional to 679.24, 1,018.80 and 643.66

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Solution

The fourth proportional to 679.24, 1,018.80 and 643.66 is: 965.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    679.24 : 1,018.80 = 643.66 : x
  2. Step 2: Convert to fraction form
    679.24/1,018.80 = 643.66/x
  3. Step 3: Cross multiply
    679.24x = 1,018.80 × 643.66
  4. Step 4: Simplify right side
    679.24x = 655,760.81
  5. Step 5: Solve for x
    x = 655,760.81/679.24
  6. Step 6: Final answer
    x = 965.43

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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.