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Finding the Fourth Proportional to 987.08, 1,479.14 and 780.80

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Solution

The fourth proportional to 987.08, 1,479.14 and 780.80 is: 1,170.03

Step by Step Solution

  1. Step 1: Write the proportion equation
    987.08 : 1,479.14 = 780.80 : x
  2. Step 2: Convert to fraction form
    987.08/1,479.14 = 780.80/x
  3. Step 3: Cross multiply
    987.08x = 1,479.14 × 780.80
  4. Step 4: Simplify right side
    987.08x = 1,154,908.61
  5. Step 5: Solve for x
    x = 1,154,908.61/987.08
  6. Step 6: Final answer
    x = 1,170.03

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.