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Finding the Fourth Proportional to 1,979.28, 2,970.45 and 939.78

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Solution

The fourth proportional to 1,979.28, 2,970.45 and 939.78 is: 1,410.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,979.28 : 2,970.45 = 939.78 : x
  2. Step 2: Convert to fraction form
    1,979.28/2,970.45 = 939.78/x
  3. Step 3: Cross multiply
    1,979.28x = 2,970.45 × 939.78
  4. Step 4: Simplify right side
    1,979.28x = 2,791,569.50
  5. Step 5: Solve for x
    x = 2,791,569.50/1,979.28
  6. Step 6: Final answer
    x = 1,410.40

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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.