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Finding the Fourth Proportional to 1,319.70, 1,979.85 and 771.60

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Solution

The fourth proportional to 1,319.70, 1,979.85 and 771.60 is: 1,157.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,319.70 : 1,979.85 = 771.60 : x
  2. Step 2: Convert to fraction form
    1,319.70/1,979.85 = 771.60/x
  3. Step 3: Cross multiply
    1,319.70x = 1,979.85 × 771.60
  4. Step 4: Simplify right side
    1,319.70x = 1,527,652.26
  5. Step 5: Solve for x
    x = 1,527,652.26/1,319.70
  6. Step 6: Final answer
    x = 1,157.58

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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.