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Finding the Fourth Proportional to 818.79, 1,129.95 and 487.28

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Solution

The fourth proportional to 818.79, 1,129.95 and 487.28 is: 672.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    818.79 : 1,129.95 = 487.28 : x
  2. Step 2: Convert to fraction form
    818.79/1,129.95 = 487.28/x
  3. Step 3: Cross multiply
    818.79x = 1,129.95 × 487.28
  4. Step 4: Simplify right side
    818.79x = 550,596.39
  5. Step 5: Solve for x
    x = 550,596.39/818.79
  6. Step 6: Final answer
    x = 672.45

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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.