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Finding the Fourth Proportional to 990.32, 1,366.66 and 641.61

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Solution

The fourth proportional to 990.32, 1,366.66 and 641.61 is: 885.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    990.32 : 1,366.66 = 641.61 : x
  2. Step 2: Convert to fraction form
    990.32/1,366.66 = 641.61/x
  3. Step 3: Cross multiply
    990.32x = 1,366.66 × 641.61
  4. Step 4: Simplify right side
    990.32x = 876,862.72
  5. Step 5: Solve for x
    x = 876,862.72/990.32
  6. Step 6: Final answer
    x = 885.43

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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.