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Finding the Fourth Proportional to 1,221.61, 1,831.71 and 388.51

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Solution

The fourth proportional to 1,221.61, 1,831.71 and 388.51 is: 582.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,221.61 : 1,831.71 = 388.51 : x
  2. Step 2: Convert to fraction form
    1,221.61/1,831.71 = 388.51/x
  3. Step 3: Cross multiply
    1,221.61x = 1,831.71 × 388.51
  4. Step 4: Simplify right side
    1,221.61x = 711,637.65
  5. Step 5: Solve for x
    x = 711,637.65/1,221.61
  6. Step 6: Final answer
    x = 582.54

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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.