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Finding the Fourth Proportional to 491.46, 678.20 and 278.75

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Solution

The fourth proportional to 491.46, 678.20 and 278.75 is: 384.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    491.46 : 678.20 = 278.75 : x
  2. Step 2: Convert to fraction form
    491.46/678.20 = 278.75/x
  3. Step 3: Cross multiply
    491.46x = 678.20 × 278.75
  4. Step 4: Simplify right side
    491.46x = 189,048.25
  5. Step 5: Solve for x
    x = 189,048.25/491.46
  6. Step 6: Final answer
    x = 384.67

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.