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Finding the Fourth Proportional to 931.49, 1,285.89 and 721.19

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Solution

The fourth proportional to 931.49, 1,285.89 and 721.19 is: 995.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    931.49 : 1,285.89 = 721.19 : x
  2. Step 2: Convert to fraction form
    931.49/1,285.89 = 721.19/x
  3. Step 3: Cross multiply
    931.49x = 1,285.89 × 721.19
  4. Step 4: Simplify right side
    931.49x = 927,371.01
  5. Step 5: Solve for x
    x = 927,371.01/931.49
  6. Step 6: Final answer
    x = 995.58

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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.