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Finding the Fourth Proportional to 780.76, 1,078.87 and 742.80

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Solution

The fourth proportional to 780.76, 1,078.87 and 742.80 is: 1,026.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.76 : 1,078.87 = 742.80 : x
  2. Step 2: Convert to fraction form
    780.76/1,078.87 = 742.80/x
  3. Step 3: Cross multiply
    780.76x = 1,078.87 × 742.80
  4. Step 4: Simplify right side
    780.76x = 801,384.64
  5. Step 5: Solve for x
    x = 801,384.64/780.76
  6. Step 6: Final answer
    x = 1,026.42

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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.