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Finding the Fourth Proportional to 718.64, 991.40 and 423.78

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Solution

The fourth proportional to 718.64, 991.40 and 423.78 is: 584.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    718.64 : 991.40 = 423.78 : x
  2. Step 2: Convert to fraction form
    718.64/991.40 = 423.78/x
  3. Step 3: Cross multiply
    718.64x = 991.40 × 423.78
  4. Step 4: Simplify right side
    718.64x = 420,135.49
  5. Step 5: Solve for x
    x = 420,135.49/718.64
  6. Step 6: Final answer
    x = 584.63

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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.