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Finding the Fourth Proportional to 781.50, 1,172.64 and 521.64

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Solution

The fourth proportional to 781.50, 1,172.64 and 521.64 is: 782.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    781.50 : 1,172.64 = 521.64 : x
  2. Step 2: Convert to fraction form
    781.50/1,172.64 = 521.64/x
  3. Step 3: Cross multiply
    781.50x = 1,172.64 × 521.64
  4. Step 4: Simplify right side
    781.50x = 611,695.93
  5. Step 5: Solve for x
    x = 611,695.93/781.50
  6. Step 6: Final answer
    x = 782.72

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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.