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Finding the Fourth Proportional to 1,720.20, 2,580.30 and 989.40

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Solution

The fourth proportional to 1,720.20, 2,580.30 and 989.40 is: 1,484.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,720.20 : 2,580.30 = 989.40 : x
  2. Step 2: Convert to fraction form
    1,720.20/2,580.30 = 989.40/x
  3. Step 3: Cross multiply
    1,720.20x = 2,580.30 × 989.40
  4. Step 4: Simplify right side
    1,720.20x = 2,552,948.82
  5. Step 5: Solve for x
    x = 2,552,948.82/1,720.20
  6. Step 6: Final answer
    x = 1,484.10

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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.