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Finding the Fourth Proportional to 670.76, 1,005.80 and 280.65

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Solution

The fourth proportional to 670.76, 1,005.80 and 280.65 is: 420.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    670.76 : 1,005.80 = 280.65 : x
  2. Step 2: Convert to fraction form
    670.76/1,005.80 = 280.65/x
  3. Step 3: Cross multiply
    670.76x = 1,005.80 × 280.65
  4. Step 4: Simplify right side
    670.76x = 282,280.14
  5. Step 5: Solve for x
    x = 282,280.14/670.76
  6. Step 6: Final answer
    x = 420.84

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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.