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Finding the Fourth Proportional to 1,220.64, 1,831.56 and 643.56

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Solution

The fourth proportional to 1,220.64, 1,831.56 and 643.56 is: 965.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,220.64 : 1,831.56 = 643.56 : x
  2. Step 2: Convert to fraction form
    1,220.64/1,831.56 = 643.56/x
  3. Step 3: Cross multiply
    1,220.64x = 1,831.56 × 643.56
  4. Step 4: Simplify right side
    1,220.64x = 1,178,718.75
  5. Step 5: Solve for x
    x = 1,178,718.75/1,220.64
  6. Step 6: Final answer
    x = 965.66

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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.