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Finding the Fourth Proportional to 1,391.22, 1,919.86 and 770.22

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Solution

The fourth proportional to 1,391.22, 1,919.86 and 770.22 is: 1,062.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,391.22 : 1,919.86 = 770.22 : x
  2. Step 2: Convert to fraction form
    1,391.22/1,919.86 = 770.22/x
  3. Step 3: Cross multiply
    1,391.22x = 1,919.86 × 770.22
  4. Step 4: Simplify right side
    1,391.22x = 1,478,714.57
  5. Step 5: Solve for x
    x = 1,478,714.57/1,391.22
  6. Step 6: Final answer
    x = 1,062.89

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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.