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Finding the Fourth Proportional to 1,391.76, 1,919.73 and 971.95

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Solution

The fourth proportional to 1,391.76, 1,919.73 and 971.95 is: 1,340.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,391.76 : 1,919.73 = 971.95 : x
  2. Step 2: Convert to fraction form
    1,391.76/1,919.73 = 971.95/x
  3. Step 3: Cross multiply
    1,391.76x = 1,919.73 × 971.95
  4. Step 4: Simplify right side
    1,391.76x = 1,865,881.57
  5. Step 5: Solve for x
    x = 1,865,881.57/1,391.76
  6. Step 6: Final answer
    x = 1,340.67

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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.