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Finding the Fourth Proportional to 987.36, 1,363.20 and 778.08

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Solution

The fourth proportional to 987.36, 1,363.20 and 778.08 is: 1,074.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    987.36 : 1,363.20 = 778.08 : x
  2. Step 2: Convert to fraction form
    987.36/1,363.20 = 778.08/x
  3. Step 3: Cross multiply
    987.36x = 1,363.20 × 778.08
  4. Step 4: Simplify right side
    987.36x = 1,060,678.66
  5. Step 5: Solve for x
    x = 1,060,678.66/987.36
  6. Step 6: Final answer
    x = 1,074.26

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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.