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Finding the Fourth Proportional to 515.19, 711.09 and 305.43

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Solution

The fourth proportional to 515.19, 711.09 and 305.43 is: 421.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    515.19 : 711.09 = 305.43 : x
  2. Step 2: Convert to fraction form
    515.19/711.09 = 305.43/x
  3. Step 3: Cross multiply
    515.19x = 711.09 × 305.43
  4. Step 4: Simplify right side
    515.19x = 217,188.22
  5. Step 5: Solve for x
    x = 217,188.22/515.19
  6. Step 6: Final answer
    x = 421.57

Related Problems

Find fourth proportional to 257.60, 355.55 and 152.72
Half scale
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Double scale
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Similar ratio
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1.5x scale

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.