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Finding the Fourth Proportional to 722.40, 1,078.35 and 669

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Solution

The fourth proportional to 722.40, 1,078.35 and 669 is: 998.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    722.40 : 1,078.35 = 669 : x
  2. Step 2: Convert to fraction form
    722.40/1,078.35 = 669/x
  3. Step 3: Cross multiply
    722.40x = 1,078.35 × 669
  4. Step 4: Simplify right side
    722.40x = 721,416.15
  5. Step 5: Solve for x
    x = 721,416.15/722.40
  6. Step 6: Final answer
    x = 998.64

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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.