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Finding the Fourth Proportional to 938.58, 1,292.49 and 643.38

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Solution

The fourth proportional to 938.58, 1,292.49 and 643.38 is: 885.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    938.58 : 1,292.49 = 643.38 : x
  2. Step 2: Convert to fraction form
    938.58/1,292.49 = 643.38/x
  3. Step 3: Cross multiply
    938.58x = 1,292.49 × 643.38
  4. Step 4: Simplify right side
    938.58x = 831,562.22
  5. Step 5: Solve for x
    x = 831,562.22/938.58
  6. Step 6: Final answer
    x = 885.98

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1.5x scale

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.