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Finding the Fourth Proportional to 870.74, 1,199.07 and 815.15

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Solution

The fourth proportional to 870.74, 1,199.07 and 815.15 is: 1,122.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    870.74 : 1,199.07 = 815.15 : x
  2. Step 2: Convert to fraction form
    870.74/1,199.07 = 815.15/x
  3. Step 3: Cross multiply
    870.74x = 1,199.07 × 815.15
  4. Step 4: Simplify right side
    870.74x = 977,415.92
  5. Step 5: Solve for x
    x = 977,415.92/870.74
  6. Step 6: Final answer
    x = 1,122.52

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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.