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Finding the Fourth Proportional to 990.27, 1,484.60 and 642.78

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Solution

The fourth proportional to 990.27, 1,484.60 and 642.78 is: 963.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    990.27 : 1,484.60 = 642.78 : x
  2. Step 2: Convert to fraction form
    990.27/1,484.60 = 642.78/x
  3. Step 3: Cross multiply
    990.27x = 1,484.60 × 642.78
  4. Step 4: Simplify right side
    990.27x = 954,267.97
  5. Step 5: Solve for x
    x = 954,267.97/990.27
  6. Step 6: Final answer
    x = 963.64

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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.