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Finding the Fourth Proportional to 810.30, 1,215.40 and 316.86

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Solution

The fourth proportional to 810.30, 1,215.40 and 316.86 is: 475.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    810.30 : 1,215.40 = 316.86 : x
  2. Step 2: Convert to fraction form
    810.30/1,215.40 = 316.86/x
  3. Step 3: Cross multiply
    810.30x = 1,215.40 × 316.86
  4. Step 4: Simplify right side
    810.30x = 385,111.64
  5. Step 5: Solve for x
    x = 385,111.64/810.30
  6. Step 6: Final answer
    x = 475.27

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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.