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Finding the Fourth Proportional to 1,378.80, 1,903.68 and 855.60

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Solution

The fourth proportional to 1,378.80, 1,903.68 and 855.60 is: 1,181.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,378.80 : 1,903.68 = 855.60 : x
  2. Step 2: Convert to fraction form
    1,378.80/1,903.68 = 855.60/x
  3. Step 3: Cross multiply
    1,378.80x = 1,903.68 × 855.60
  4. Step 4: Simplify right side
    1,378.80x = 1,628,788.61
  5. Step 5: Solve for x
    x = 1,628,788.61/1,378.80
  6. Step 6: Final answer
    x = 1,181.31

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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.