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Finding the Fourth Proportional to 891.38, 1,228.43 and 642.29

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Solution

The fourth proportional to 891.38, 1,228.43 and 642.29 is: 885.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    891.38 : 1,228.43 = 642.29 : x
  2. Step 2: Convert to fraction form
    891.38/1,228.43 = 642.29/x
  3. Step 3: Cross multiply
    891.38x = 1,228.43 × 642.29
  4. Step 4: Simplify right side
    891.38x = 789,003.77
  5. Step 5: Solve for x
    x = 789,003.77/891.38
  6. Step 6: Final answer
    x = 885.15

Related Problems

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Half scale
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Double scale
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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.