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Finding the Fourth Proportional to 763.40, 1,142.58 and 438.68

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Solution

The fourth proportional to 763.40, 1,142.58 and 438.68 is: 656.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    763.40 : 1,142.58 = 438.68 : x
  2. Step 2: Convert to fraction form
    763.40/1,142.58 = 438.68/x
  3. Step 3: Cross multiply
    763.40x = 1,142.58 × 438.68
  4. Step 4: Simplify right side
    763.40x = 501,226.99
  5. Step 5: Solve for x
    x = 501,226.99/763.40
  6. Step 6: Final answer
    x = 656.57

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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.