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Finding the Fourth Proportional to 781.64, 1,172.64 and 313.14

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Solution

The fourth proportional to 781.64, 1,172.64 and 313.14 is: 469.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    781.64 : 1,172.64 = 313.14 : x
  2. Step 2: Convert to fraction form
    781.64/1,172.64 = 313.14/x
  3. Step 3: Cross multiply
    781.64x = 1,172.64 × 313.14
  4. Step 4: Simplify right side
    781.64x = 367,200.49
  5. Step 5: Solve for x
    x = 367,200.49/781.64
  6. Step 6: Final answer
    x = 469.78

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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.