Home / 221.13-305.15-122.90

Finding the Fourth Proportional to 221.13, 305.15 and 122.90

Calculator

Solution

The fourth proportional to 221.13, 305.15 and 122.90 is: 169.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    221.13 : 305.15 = 122.90 : x
  2. Step 2: Convert to fraction form
    221.13/305.15 = 122.90/x
  3. Step 3: Cross multiply
    221.13x = 305.15 × 122.90
  4. Step 4: Simplify right side
    221.13x = 37,500.79
  5. Step 5: Solve for x
    x = 37,500.79/221.13
  6. Step 6: Final answer
    x = 169.59

Related Problems

Find fourth proportional to 110.57, 152.57 and 61.45
Half scale
Find fourth proportional to 442.26, 610.29 and 245.79
Double scale
Find fourth proportional to 222.13, 306.52 and 123.90
Similar ratio
Find fourth proportional to 331.70, 457.72 and 184.34
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.