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Finding the Fourth Proportional to 891.11, 1,229.85 and 642.76

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Solution

The fourth proportional to 891.11, 1,229.85 and 642.76 is: 887.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    891.11 : 1,229.85 = 642.76 : x
  2. Step 2: Convert to fraction form
    891.11/1,229.85 = 642.76/x
  3. Step 3: Cross multiply
    891.11x = 1,229.85 × 642.76
  4. Step 4: Simplify right side
    891.11x = 790,498.39
  5. Step 5: Solve for x
    x = 790,498.39/891.11
  6. Step 6: Final answer
    x = 887.10

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.