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Finding the Fourth Proportional to 997.21, 1,376.37 and 642.89

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Solution

The fourth proportional to 997.21, 1,376.37 and 642.89 is: 887.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    997.21 : 1,376.37 = 642.89 : x
  2. Step 2: Convert to fraction form
    997.21/1,376.37 = 642.89/x
  3. Step 3: Cross multiply
    997.21x = 1,376.37 × 642.89
  4. Step 4: Simplify right side
    997.21x = 884,848.40
  5. Step 5: Solve for x
    x = 884,848.40/997.21
  6. Step 6: Final answer
    x = 887.32

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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.