Home / 20,806.40-31,209.60-12,915.20

Finding the Fourth Proportional to 20,806.40, 31,209.60 and 12,915.20

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Solution

The fourth proportional to 20,806.40, 31,209.60 and 12,915.20 is: 19,372.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    20,806.40 : 31,209.60 = 12,915.20 : x
  2. Step 2: Convert to fraction form
    20,806.40/31,209.60 = 12,915.20/x
  3. Step 3: Cross multiply
    20,806.40x = 31,209.60 × 12,915.20
  4. Step 4: Simplify right side
    20,806.40x = 403,078,225.92
  5. Step 5: Solve for x
    x = 403,078,225.92/20,806.40
  6. Step 6: Final answer
    x = 19,372.80

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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.