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Finding the Fourth Proportional to 810.06, 1,215.25 and 420.25

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Solution

The fourth proportional to 810.06, 1,215.25 and 420.25 is: 630.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    810.06 : 1,215.25 = 420.25 : x
  2. Step 2: Convert to fraction form
    810.06/1,215.25 = 420.25/x
  3. Step 3: Cross multiply
    810.06x = 1,215.25 × 420.25
  4. Step 4: Simplify right side
    810.06x = 510,708.81
  5. Step 5: Solve for x
    x = 510,708.81/810.06
  6. Step 6: Final answer
    x = 630.46

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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.