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Finding the Fourth Proportional to 1,220.21, 1,684.42 and 778.69

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Solution

The fourth proportional to 1,220.21, 1,684.42 and 778.69 is: 1,074.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,220.21 : 1,684.42 = 778.69 : x
  2. Step 2: Convert to fraction form
    1,220.21/1,684.42 = 778.69/x
  3. Step 3: Cross multiply
    1,220.21x = 1,684.42 × 778.69
  4. Step 4: Simplify right side
    1,220.21x = 1,311,641.01
  5. Step 5: Solve for x
    x = 1,311,641.01/1,220.21
  6. Step 6: Final answer
    x = 1,074.93

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Double scale
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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.