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Finding the Fourth Proportional to 885.39, 1,221.78 and 492.40

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Solution

The fourth proportional to 885.39, 1,221.78 and 492.40 is: 679.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    885.39 : 1,221.78 = 492.40 : x
  2. Step 2: Convert to fraction form
    885.39/1,221.78 = 492.40/x
  3. Step 3: Cross multiply
    885.39x = 1,221.78 × 492.40
  4. Step 4: Simplify right side
    885.39x = 601,604.47
  5. Step 5: Solve for x
    x = 601,604.47/885.39
  6. Step 6: Final answer
    x = 679.48

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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.