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Finding the Fourth Proportional to 1,539.38, 2,124.40 and 840.78

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Solution

The fourth proportional to 1,539.38, 2,124.40 and 840.78 is: 1,160.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,539.38 : 2,124.40 = 840.78 : x
  2. Step 2: Convert to fraction form
    1,539.38/2,124.40 = 840.78/x
  3. Step 3: Cross multiply
    1,539.38x = 2,124.40 × 840.78
  4. Step 4: Simplify right side
    1,539.38x = 1,786,153.03
  5. Step 5: Solve for x
    x = 1,786,153.03/1,539.38
  6. Step 6: Final answer
    x = 1,160.31

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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.