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Finding the Fourth Proportional to 1,390.56, 1,919.19 and 830.85

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Solution

The fourth proportional to 1,390.56, 1,919.19 and 830.85 is: 1,146.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,390.56 : 1,919.19 = 830.85 : x
  2. Step 2: Convert to fraction form
    1,390.56/1,919.19 = 830.85/x
  3. Step 3: Cross multiply
    1,390.56x = 1,919.19 × 830.85
  4. Step 4: Simplify right side
    1,390.56x = 1,594,559.01
  5. Step 5: Solve for x
    x = 1,594,559.01/1,390.56
  6. Step 6: Final answer
    x = 1,146.70

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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.