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Finding the Fourth Proportional to 687, 948.78 and 479.64

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Solution

The fourth proportional to 687, 948.78 and 479.64 is: 662.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    687 : 948.78 = 479.64 : x
  2. Step 2: Convert to fraction form
    687/948.78 = 479.64/x
  3. Step 3: Cross multiply
    687x = 948.78 × 479.64
  4. Step 4: Simplify right side
    687x = 455,072.84
  5. Step 5: Solve for x
    x = 455,072.84/687
  6. Step 6: Final answer
    x = 662.41

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.