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Finding the Fourth Proportional to 678.15, 1,017.53 and 312.74

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Solution

The fourth proportional to 678.15, 1,017.53 and 312.74 is: 469.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.15 : 1,017.53 = 312.74 : x
  2. Step 2: Convert to fraction form
    678.15/1,017.53 = 312.74/x
  3. Step 3: Cross multiply
    678.15x = 1,017.53 × 312.74
  4. Step 4: Simplify right side
    678.15x = 318,222.33
  5. Step 5: Solve for x
    x = 318,222.33/678.15
  6. Step 6: Final answer
    x = 469.25

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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.