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Finding the Fourth Proportional to 1,428.61, 1,970.87 and 1,008.90

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Solution

The fourth proportional to 1,428.61, 1,970.87 and 1,008.90 is: 1,391.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,428.61 : 1,970.87 = 1,008.90 : x
  2. Step 2: Convert to fraction form
    1,428.61/1,970.87 = 1,008.90/x
  3. Step 3: Cross multiply
    1,428.61x = 1,970.87 × 1,008.90
  4. Step 4: Simplify right side
    1,428.61x = 1,988,400.16
  5. Step 5: Solve for x
    x = 1,988,400.16/1,428.61
  6. Step 6: Final answer
    x = 1,391.84

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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.