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Finding the Fourth Proportional to 818.70, 1,129.75 and 487.15

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Solution

The fourth proportional to 818.70, 1,129.75 and 487.15 is: 672.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    818.70 : 1,129.75 = 487.15 : x
  2. Step 2: Convert to fraction form
    818.70/1,129.75 = 487.15/x
  3. Step 3: Cross multiply
    818.70x = 1,129.75 × 487.15
  4. Step 4: Simplify right side
    818.70x = 550,353.67
  5. Step 5: Solve for x
    x = 550,353.67/818.70
  6. Step 6: Final answer
    x = 672.23

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1.5x scale

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.