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Finding the Fourth Proportional to 1,221, 1,831.09 and 399.09

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Solution

The fourth proportional to 1,221, 1,831.09 and 399.09 is: 598.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,221 : 1,831.09 = 399.09 : x
  2. Step 2: Convert to fraction form
    1,221/1,831.09 = 399.09/x
  3. Step 3: Cross multiply
    1,221x = 1,831.09 × 399.09
  4. Step 4: Simplify right side
    1,221x = 730,769.71
  5. Step 5: Solve for x
    x = 730,769.71/1,221
  6. Step 6: Final answer
    x = 598.50

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Double scale
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Similar ratio
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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.