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Finding the Fourth Proportional to 990.75, 1,486.17 and 260.31

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Solution

The fourth proportional to 990.75, 1,486.17 and 260.31 is: 390.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    990.75 : 1,486.17 = 260.31 : x
  2. Step 2: Convert to fraction form
    990.75/1,486.17 = 260.31/x
  3. Step 3: Cross multiply
    990.75x = 1,486.17 × 260.31
  4. Step 4: Simplify right side
    990.75x = 386,864.91
  5. Step 5: Solve for x
    x = 386,864.91/990.75
  6. Step 6: Final answer
    x = 390.48

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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.