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Finding the Fourth Proportional to 933.98, 1,289.40 and 639.68

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Solution

The fourth proportional to 933.98, 1,289.40 and 639.68 is: 883.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    933.98 : 1,289.40 = 639.68 : x
  2. Step 2: Convert to fraction form
    933.98/1,289.40 = 639.68/x
  3. Step 3: Cross multiply
    933.98x = 1,289.40 × 639.68
  4. Step 4: Simplify right side
    933.98x = 824,803.39
  5. Step 5: Solve for x
    x = 824,803.39/933.98
  6. Step 6: Final answer
    x = 883.11

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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.