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Finding the Fourth Proportional to 819, 1,128.96 and 720.18

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Solution

The fourth proportional to 819, 1,128.96 and 720.18 is: 992.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    819 : 1,128.96 = 720.18 : x
  2. Step 2: Convert to fraction form
    819/1,128.96 = 720.18/x
  3. Step 3: Cross multiply
    819x = 1,128.96 × 720.18
  4. Step 4: Simplify right side
    819x = 813,054.41
  5. Step 5: Solve for x
    x = 813,054.41/819
  6. Step 6: Final answer
    x = 992.74

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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.