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Finding the Fourth Proportional to 1,419.39, 2,129.64 and 639.18

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Solution

The fourth proportional to 1,419.39, 2,129.64 and 639.18 is: 959.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,419.39 : 2,129.64 = 639.18 : x
  2. Step 2: Convert to fraction form
    1,419.39/2,129.64 = 639.18/x
  3. Step 3: Cross multiply
    1,419.39x = 2,129.64 × 639.18
  4. Step 4: Simplify right side
    1,419.39x = 1,361,223.30
  5. Step 5: Solve for x
    x = 1,361,223.30/1,419.39
  6. Step 6: Final answer
    x = 959.02

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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.