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Finding the Fourth Proportional to 870.50, 1,311.86 and 783.93

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Solution

The fourth proportional to 870.50, 1,311.86 and 783.93 is: 1,181.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    870.50 : 1,311.86 = 783.93 : x
  2. Step 2: Convert to fraction form
    870.50/1,311.86 = 783.93/x
  3. Step 3: Cross multiply
    870.50x = 1,311.86 × 783.93
  4. Step 4: Simplify right side
    870.50x = 1,028,406.41
  5. Step 5: Solve for x
    x = 1,028,406.41/870.50
  6. Step 6: Final answer
    x = 1,181.40

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.