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Finding the Fourth Proportional to 1,421.40, 1,961.53 and 831.82

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Solution

The fourth proportional to 1,421.40, 1,961.53 and 831.82 is: 1,147.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,421.40 : 1,961.53 = 831.82 : x
  2. Step 2: Convert to fraction form
    1,421.40/1,961.53 = 831.82/x
  3. Step 3: Cross multiply
    1,421.40x = 1,961.53 × 831.82
  4. Step 4: Simplify right side
    1,421.40x = 1,631,635.73
  5. Step 5: Solve for x
    x = 1,631,635.73/1,421.40
  6. Step 6: Final answer
    x = 1,147.91

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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.