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Finding the Fourth Proportional to 768.75, 1,153.13 and 312.75

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Solution

The fourth proportional to 768.75, 1,153.13 and 312.75 is: 469.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    768.75 : 1,153.13 = 312.75 : x
  2. Step 2: Convert to fraction form
    768.75/1,153.13 = 312.75/x
  3. Step 3: Cross multiply
    768.75x = 1,153.13 × 312.75
  4. Step 4: Simplify right side
    768.75x = 360,639.84
  5. Step 5: Solve for x
    x = 360,639.84/768.75
  6. Step 6: Final answer
    x = 469.13

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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.