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Finding the Fourth Proportional to 1,220.76, 1,831.68 and 643.68

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Solution

The fourth proportional to 1,220.76, 1,831.68 and 643.68 is: 965.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,220.76 : 1,831.68 = 643.68 : x
  2. Step 2: Convert to fraction form
    1,220.76/1,831.68 = 643.68/x
  3. Step 3: Cross multiply
    1,220.76x = 1,831.68 × 643.68
  4. Step 4: Simplify right side
    1,220.76x = 1,179,015.78
  5. Step 5: Solve for x
    x = 1,179,015.78/1,220.76
  6. Step 6: Final answer
    x = 965.80

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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.