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Finding the Fourth Proportional to 1,580.28, 2,179.86 and 989.78

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Solution

The fourth proportional to 1,580.28, 2,179.86 and 989.78 is: 1,365.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,580.28 : 2,179.86 = 989.78 : x
  2. Step 2: Convert to fraction form
    1,580.28/2,179.86 = 989.78/x
  3. Step 3: Cross multiply
    1,580.28x = 2,179.86 × 989.78
  4. Step 4: Simplify right side
    1,580.28x = 2,157,581.83
  5. Step 5: Solve for x
    x = 2,157,581.83/1,580.28
  6. Step 6: Final answer
    x = 1,365.32

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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.