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Finding the Fourth Proportional to 210.99, 291.16 and 128.11

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Solution

The fourth proportional to 210.99, 291.16 and 128.11 is: 176.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    210.99 : 291.16 = 128.11 : x
  2. Step 2: Convert to fraction form
    210.99/291.16 = 128.11/x
  3. Step 3: Cross multiply
    210.99x = 291.16 × 128.11
  4. Step 4: Simplify right side
    210.99x = 37,300.51
  5. Step 5: Solve for x
    x = 37,300.51/210.99
  6. Step 6: Final answer
    x = 176.79

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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.