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Finding the Fourth Proportional to 642.36, 963.72 and 209.55

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Solution

The fourth proportional to 642.36, 963.72 and 209.55 is: 314.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.36 : 963.72 = 209.55 : x
  2. Step 2: Convert to fraction form
    642.36/963.72 = 209.55/x
  3. Step 3: Cross multiply
    642.36x = 963.72 × 209.55
  4. Step 4: Simplify right side
    642.36x = 201,947.53
  5. Step 5: Solve for x
    x = 201,947.53/642.36
  6. Step 6: Final answer
    x = 314.38

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1.5x scale

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.