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Finding the Fourth Proportional to 987.60, 1,479.80 and 824.40

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Solution

The fourth proportional to 987.60, 1,479.80 and 824.40 is: 1,235.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    987.60 : 1,479.80 = 824.40 : x
  2. Step 2: Convert to fraction form
    987.60/1,479.80 = 824.40/x
  3. Step 3: Cross multiply
    987.60x = 1,479.80 × 824.40
  4. Step 4: Simplify right side
    987.60x = 1,219,947.12
  5. Step 5: Solve for x
    x = 1,219,947.12/987.60
  6. Step 6: Final answer
    x = 1,235.26

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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.