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Finding the Fourth Proportional to 859.19, 1,287.08 and 640.49

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Solution

The fourth proportional to 859.19, 1,287.08 and 640.49 is: 959.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    859.19 : 1,287.08 = 640.49 : x
  2. Step 2: Convert to fraction form
    859.19/1,287.08 = 640.49/x
  3. Step 3: Cross multiply
    859.19x = 1,287.08 × 640.49
  4. Step 4: Simplify right side
    859.19x = 824,358.67
  5. Step 5: Solve for x
    x = 824,358.67/859.19
  6. Step 6: Final answer
    x = 959.46

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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.