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Finding the Fourth Proportional to 1,381.66, 1,905.96 and 856.78

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Solution

The fourth proportional to 1,381.66, 1,905.96 and 856.78 is: 1,181.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,381.66 : 1,905.96 = 856.78 : x
  2. Step 2: Convert to fraction form
    1,381.66/1,905.96 = 856.78/x
  3. Step 3: Cross multiply
    1,381.66x = 1,905.96 × 856.78
  4. Step 4: Simplify right side
    1,381.66x = 1,632,983.64
  5. Step 5: Solve for x
    x = 1,632,983.64/1,381.66
  6. Step 6: Final answer
    x = 1,181.90

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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.