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Finding the Fourth Proportional to 13,987.20, 20,987.84 and 8,720.85

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Solution

The fourth proportional to 13,987.20, 20,987.84 and 8,720.85 is: 13,085.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    13,987.20 : 20,987.84 = 8,720.85 : x
  2. Step 2: Convert to fraction form
    13,987.20/20,987.84 = 8,720.85/x
  3. Step 3: Cross multiply
    13,987.20x = 20,987.84 × 8,720.85
  4. Step 4: Simplify right side
    13,987.20x = 183,031,804.46
  5. Step 5: Solve for x
    x = 183,031,804.46/13,987.20
  6. Step 6: Final answer
    x = 13,085.66

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1.5x scale

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.