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Finding the Fourth Proportional to 859.36, 1,289.36 and 426.40

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Solution

The fourth proportional to 859.36, 1,289.36 and 426.40 is: 639.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    859.36 : 1,289.36 = 426.40 : x
  2. Step 2: Convert to fraction form
    859.36/1,289.36 = 426.40/x
  3. Step 3: Cross multiply
    859.36x = 1,289.36 × 426.40
  4. Step 4: Simplify right side
    859.36x = 549,783.10
  5. Step 5: Solve for x
    x = 549,783.10/859.36
  6. Step 6: Final answer
    x = 639.76

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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.