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Finding the Fourth Proportional to 1,220, 1,684.16 and 778.50

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Solution

The fourth proportional to 1,220, 1,684.16 and 778.50 is: 1,074.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,220 : 1,684.16 = 778.50 : x
  2. Step 2: Convert to fraction form
    1,220/1,684.16 = 778.50/x
  3. Step 3: Cross multiply
    1,220x = 1,684.16 × 778.50
  4. Step 4: Simplify right side
    1,220x = 1,311,118.56
  5. Step 5: Solve for x
    x = 1,311,118.56/1,220
  6. Step 6: Final answer
    x = 1,074.69

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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.