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Finding the Third Proportional to 642.09 and 990.14

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Solution

The third proportional to 642.09 and 990.14 is: 1,526.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.09 : 990.14 = 990.14 : x
  2. Step 2: Convert to fraction form
    642.09/990.14 = 990.14/x
  3. Step 3: Cross multiply
    642.09x = 990.14 × 990.14
  4. Step 4: Simplify right side
    642.09x = 980,378.46
  5. Step 5: Solve for x
    x = 980,378.46/642.09
  6. Step 6: Final answer
    x = 1,526.85

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Why These Related Problems?

These problems maintain the same ratio (1.54) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.