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Finding the Fourth Proportional to 152.70, 210.74 and 87.21

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Solution

The fourth proportional to 152.70, 210.74 and 87.21 is: 120.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    152.70 : 210.74 = 87.21 : x
  2. Step 2: Convert to fraction form
    152.70/210.74 = 87.21/x
  3. Step 3: Cross multiply
    152.70x = 210.74 × 87.21
  4. Step 4: Simplify right side
    152.70x = 18,378.64
  5. Step 5: Solve for x
    x = 18,378.64/152.70
  6. Step 6: Final answer
    x = 120.36

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.