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Finding the Fourth Proportional to 646.10, 897.78 and 639.40

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Solution

The fourth proportional to 646.10, 897.78 and 639.40 is: 888.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    646.10 : 897.78 = 639.40 : x
  2. Step 2: Convert to fraction form
    646.10/897.78 = 639.40/x
  3. Step 3: Cross multiply
    646.10x = 897.78 × 639.40
  4. Step 4: Simplify right side
    646.10x = 574,040.53
  5. Step 5: Solve for x
    x = 574,040.53/646.10
  6. Step 6: Final answer
    x = 888.47

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.