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Finding the Third Proportional to 428.63 and 687.19

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Solution

The third proportional to 428.63 and 687.19 is: 1,101.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.63 : 687.19 = 687.19 : x
  2. Step 2: Convert to fraction form
    428.63/687.19 = 687.19/x
  3. Step 3: Cross multiply
    428.63x = 687.19 × 687.19
  4. Step 4: Simplify right side
    428.63x = 472,226.66
  5. Step 5: Solve for x
    x = 472,226.66/428.63
  6. Step 6: Final answer
    x = 1,101.72

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Why These Related Problems?

These problems maintain the same ratio (1.60) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.