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Finding the Third Proportional to 428 and 1,120

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Solution

The third proportional to 428 and 1,120 is: 2,930.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    428 : 1,120 = 1,120 : x
  2. Step 2: Convert to fraction form
    428/1,120 = 1,120/x
  3. Step 3: Cross multiply
    428x = 1,120 × 1,120
  4. Step 4: Simplify right side
    428x = 1,254,400
  5. Step 5: Solve for x
    x = 1,254,400/428
  6. Step 6: Final answer
    x = 2,930.84

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Why These Related Problems?

These problems maintain the same ratio (2.62) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.