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Finding the Fourth Proportional to 780.30, 1,074.64 and 648.11

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Solution

The fourth proportional to 780.30, 1,074.64 and 648.11 is: 892.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.30 : 1,074.64 = 648.11 : x
  2. Step 2: Convert to fraction form
    780.30/1,074.64 = 648.11/x
  3. Step 3: Cross multiply
    780.30x = 1,074.64 × 648.11
  4. Step 4: Simplify right side
    780.30x = 696,479.15
  5. Step 5: Solve for x
    x = 696,479.15/780.30
  6. Step 6: Final answer
    x = 892.57

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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.