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Finding the Fourth Proportional to 784.40, 1,082.34 and 489.76

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Solution

The fourth proportional to 784.40, 1,082.34 and 489.76 is: 675.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    784.40 : 1,082.34 = 489.76 : x
  2. Step 2: Convert to fraction form
    784.40/1,082.34 = 489.76/x
  3. Step 3: Cross multiply
    784.40x = 1,082.34 × 489.76
  4. Step 4: Simplify right side
    784.40x = 530,086.84
  5. Step 5: Solve for x
    x = 530,086.84/784.40
  6. Step 6: Final answer
    x = 675.79

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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.