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Finding the Fourth Proportional to 1,388.49, 1,915.70 and 891.02

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Solution

The fourth proportional to 1,388.49, 1,915.70 and 891.02 is: 1,229.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,388.49 : 1,915.70 = 891.02 : x
  2. Step 2: Convert to fraction form
    1,388.49/1,915.70 = 891.02/x
  3. Step 3: Cross multiply
    1,388.49x = 1,915.70 × 891.02
  4. Step 4: Simplify right side
    1,388.49x = 1,706,912.98
  5. Step 5: Solve for x
    x = 1,706,912.98/1,388.49
  6. Step 6: Final answer
    x = 1,229.33

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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.