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Finding the Fourth Proportional to 1.40, 2.10 and 0.90

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Solution

The fourth proportional to 1.40, 2.10 and 0.90 is: 1.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    1.40 : 2.10 = 0.90 : x
  2. Step 2: Convert to fraction form
    1.40/2.10 = 0.90/x
  3. Step 3: Cross multiply
    1.40x = 2.10 × 0.90
  4. Step 4: Simplify right side
    1.40x = 1.90
  5. Step 5: Solve for x
    x = 1.90/1.40
  6. Step 6: Final answer
    x = 1.35

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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.