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Finding the Fourth Proportional to 1,938.79, 2,908.08 and 640.21

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Solution

The fourth proportional to 1,938.79, 2,908.08 and 640.21 is: 960.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,938.79 : 2,908.08 = 640.21 : x
  2. Step 2: Convert to fraction form
    1,938.79/2,908.08 = 640.21/x
  3. Step 3: Cross multiply
    1,938.79x = 2,908.08 × 640.21
  4. Step 4: Simplify right side
    1,938.79x = 1,861,781.90
  5. Step 5: Solve for x
    x = 1,861,781.90/1,938.79
  6. Step 6: Final answer
    x = 960.28

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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.