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Finding the Fourth Proportional to 1,289.16, 1,934.42 and 639.81

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Solution

The fourth proportional to 1,289.16, 1,934.42 and 639.81 is: 960.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,289.16 : 1,934.42 = 639.81 : x
  2. Step 2: Convert to fraction form
    1,289.16/1,934.42 = 639.81/x
  3. Step 3: Cross multiply
    1,289.16x = 1,934.42 × 639.81
  4. Step 4: Simplify right side
    1,289.16x = 1,237,658.06
  5. Step 5: Solve for x
    x = 1,237,658.06/1,289.16
  6. Step 6: Final answer
    x = 960.05

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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.