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Finding the Fourth Proportional to 1,378.80, 2,068.92 and 891.72

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Solution

The fourth proportional to 1,378.80, 2,068.92 and 891.72 is: 1,338.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,378.80 : 2,068.92 = 891.72 : x
  2. Step 2: Convert to fraction form
    1,378.80/2,068.92 = 891.72/x
  3. Step 3: Cross multiply
    1,378.80x = 2,068.92 × 891.72
  4. Step 4: Simplify right side
    1,378.80x = 1,844,897.34
  5. Step 5: Solve for x
    x = 1,844,897.34/1,378.80
  6. Step 6: Final answer
    x = 1,338.05

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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.