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Finding the Fourth Proportional to 915.50, 1,263.40 and 620.87

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Solution

The fourth proportional to 915.50, 1,263.40 and 620.87 is: 856.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    915.50 : 1,263.40 = 620.87 : x
  2. Step 2: Convert to fraction form
    915.50/1,263.40 = 620.87/x
  3. Step 3: Cross multiply
    915.50x = 1,263.40 × 620.87
  4. Step 4: Simplify right side
    915.50x = 784,399.29
  5. Step 5: Solve for x
    x = 784,399.29/915.50
  6. Step 6: Final answer
    x = 856.80

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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.