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Finding the Fourth Proportional to 780.39, 1,171.32 and 561.24

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Solution

The fourth proportional to 780.39, 1,171.32 and 561.24 is: 842.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.39 : 1,171.32 = 561.24 : x
  2. Step 2: Convert to fraction form
    780.39/1,171.32 = 561.24/x
  3. Step 3: Cross multiply
    780.39x = 1,171.32 × 561.24
  4. Step 4: Simplify right side
    780.39x = 657,391.64
  5. Step 5: Solve for x
    x = 657,391.64/780.39
  6. Step 6: Final answer
    x = 842.39

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.