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Finding the Fourth Proportional to 1,579.85, 2,181.57 and 991.40

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Solution

The fourth proportional to 1,579.85, 2,181.57 and 991.40 is: 1,369.00

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,579.85 : 2,181.57 = 991.40 : x
  2. Step 2: Convert to fraction form
    1,579.85/2,181.57 = 991.40/x
  3. Step 3: Cross multiply
    1,579.85x = 2,181.57 × 991.40
  4. Step 4: Simplify right side
    1,579.85x = 2,162,808.50
  5. Step 5: Solve for x
    x = 2,162,808.50/1,579.85
  6. Step 6: Final answer
    x = 1,369.00

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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.