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Finding the Fourth Proportional to 780.55, 1,171.53 and 415.64

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Solution

The fourth proportional to 780.55, 1,171.53 and 415.64 is: 623.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.55 : 1,171.53 = 415.64 : x
  2. Step 2: Convert to fraction form
    780.55/1,171.53 = 415.64/x
  3. Step 3: Cross multiply
    780.55x = 1,171.53 × 415.64
  4. Step 4: Simplify right side
    780.55x = 486,937.66
  5. Step 5: Solve for x
    x = 486,937.66/780.55
  6. Step 6: Final answer
    x = 623.84

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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.