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Finding the Third Proportional to 420.75 and 915.19

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Solution

The third proportional to 420.75 and 915.19 is: 1,990.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.75 : 915.19 = 915.19 : x
  2. Step 2: Convert to fraction form
    420.75/915.19 = 915.19/x
  3. Step 3: Cross multiply
    420.75x = 915.19 × 915.19
  4. Step 4: Simplify right side
    420.75x = 837,568.16
  5. Step 5: Solve for x
    x = 837,568.16/420.75
  6. Step 6: Final answer
    x = 1,990.66

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Why These Related Problems?

These problems maintain the same ratio (2.18) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.