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Finding the Fourth Proportional to 1,276.20, 1,761.15 and 778.74

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Solution

The fourth proportional to 1,276.20, 1,761.15 and 778.74 is: 1,074.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,276.20 : 1,761.15 = 778.74 : x
  2. Step 2: Convert to fraction form
    1,276.20/1,761.15 = 778.74/x
  3. Step 3: Cross multiply
    1,276.20x = 1,761.15 × 778.74
  4. Step 4: Simplify right side
    1,276.20x = 1,371,477.95
  5. Step 5: Solve for x
    x = 1,371,477.95/1,276.20
  6. Step 6: Final answer
    x = 1,074.66

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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.