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Finding the Fourth Proportional to 1,991.70, 2,987.55 and 1,878.30

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Solution

The fourth proportional to 1,991.70, 2,987.55 and 1,878.30 is: 2,817.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,991.70 : 2,987.55 = 1,878.30 : x
  2. Step 2: Convert to fraction form
    1,991.70/2,987.55 = 1,878.30/x
  3. Step 3: Cross multiply
    1,991.70x = 2,987.55 × 1,878.30
  4. Step 4: Simplify right side
    1,991.70x = 5,611,515.17
  5. Step 5: Solve for x
    x = 5,611,515.17/1,991.70
  6. Step 6: Final answer
    x = 2,817.45

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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.