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Finding the Fourth Proportional to 210.51, 315.72 and 66.20

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Solution

The fourth proportional to 210.51, 315.72 and 66.20 is: 99.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    210.51 : 315.72 = 66.20 : x
  2. Step 2: Convert to fraction form
    210.51/315.72 = 66.20/x
  3. Step 3: Cross multiply
    210.51x = 315.72 × 66.20
  4. Step 4: Simplify right side
    210.51x = 20,899.09
  5. Step 5: Solve for x
    x = 20,899.09/210.51
  6. Step 6: Final answer
    x = 99.28

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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.