Home / 281.21-421.85-75.78

Finding the Fourth Proportional to 281.21, 421.85 and 75.78

Calculator

Solution

The fourth proportional to 281.21, 421.85 and 75.78 is: 113.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    281.21 : 421.85 = 75.78 : x
  2. Step 2: Convert to fraction form
    281.21/421.85 = 75.78/x
  3. Step 3: Cross multiply
    281.21x = 421.85 × 75.78
  4. Step 4: Simplify right side
    281.21x = 31,967.41
  5. Step 5: Solve for x
    x = 31,967.41/281.21
  6. Step 6: Final answer
    x = 113.68

Related Problems

Find fourth proportional to 140.60, 210.92 and 37.89
Half scale
Find fourth proportional to 562.41, 843.69 and 151.56
Double scale
Find fourth proportional to 282.21, 423.35 and 76.78
Similar ratio
Find fourth proportional to 421.81, 632.77 and 113.67
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.