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Finding the Fourth Proportional to 715.84, 987.88 and 421.08

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Solution

The fourth proportional to 715.84, 987.88 and 421.08 is: 581.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    715.84 : 987.88 = 421.08 : x
  2. Step 2: Convert to fraction form
    715.84/987.88 = 421.08/x
  3. Step 3: Cross multiply
    715.84x = 987.88 × 421.08
  4. Step 4: Simplify right side
    715.84x = 415,976.51
  5. Step 5: Solve for x
    x = 415,976.51/715.84
  6. Step 6: Final answer
    x = 581.10

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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.