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Finding the Fourth Proportional to 917.75, 1,376.80 and 430.81

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Solution

The fourth proportional to 917.75, 1,376.80 and 430.81 is: 646.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    917.75 : 1,376.80 = 430.81 : x
  2. Step 2: Convert to fraction form
    917.75/1,376.80 = 430.81/x
  3. Step 3: Cross multiply
    917.75x = 1,376.80 × 430.81
  4. Step 4: Simplify right side
    917.75x = 593,134.69
  5. Step 5: Solve for x
    x = 593,134.69/917.75
  6. Step 6: Final answer
    x = 646.29

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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.