Home / 220.64-330.87-81.78

Finding the Fourth Proportional to 220.64, 330.87 and 81.78

Calculator

Solution

The fourth proportional to 220.64, 330.87 and 81.78 is: 122.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    220.64 : 330.87 = 81.78 : x
  2. Step 2: Convert to fraction form
    220.64/330.87 = 81.78/x
  3. Step 3: Cross multiply
    220.64x = 330.87 × 81.78
  4. Step 4: Simplify right side
    220.64x = 27,058.55
  5. Step 5: Solve for x
    x = 27,058.55/220.64
  6. Step 6: Final answer
    x = 122.64

Related Problems

Find fourth proportional to 110.32, 165.44 and 40.89
Half scale
Find fourth proportional to 441.28, 661.74 and 163.56
Double scale
Find fourth proportional to 221.64, 332.37 and 82.78
Similar ratio
Find fourth proportional to 330.96, 496.31 and 122.67
1.5x scale

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.