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Finding the Fourth Proportional to 990.81, 1,486.11 and 260.29

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Solution

The fourth proportional to 990.81, 1,486.11 and 260.29 is: 390.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    990.81 : 1,486.11 = 260.29 : x
  2. Step 2: Convert to fraction form
    990.81/1,486.11 = 260.29/x
  3. Step 3: Cross multiply
    990.81x = 1,486.11 × 260.29
  4. Step 4: Simplify right side
    990.81x = 386,819.57
  5. Step 5: Solve for x
    x = 386,819.57/990.81
  6. Step 6: Final answer
    x = 390.41

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Double scale
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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.