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Finding the Fourth Proportional to 716.40, 988.62 and 421.60

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Solution

The fourth proportional to 716.40, 988.62 and 421.60 is: 581.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    716.40 : 988.62 = 421.60 : x
  2. Step 2: Convert to fraction form
    716.40/988.62 = 421.60/x
  3. Step 3: Cross multiply
    716.40x = 988.62 × 421.60
  4. Step 4: Simplify right side
    716.40x = 416,802.19
  5. Step 5: Solve for x
    x = 416,802.19/716.40
  6. Step 6: Final answer
    x = 581.80

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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.