Home / 930.21-1,395.12-280.80

Finding the Fourth Proportional to 930.21, 1,395.12 and 280.80

Calculator

Solution

The fourth proportional to 930.21, 1,395.12 and 280.80 is: 421.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    930.21 : 1,395.12 = 280.80 : x
  2. Step 2: Convert to fraction form
    930.21/1,395.12 = 280.80/x
  3. Step 3: Cross multiply
    930.21x = 1,395.12 × 280.80
  4. Step 4: Simplify right side
    930.21x = 391,749.70
  5. Step 5: Solve for x
    x = 391,749.70/930.21
  6. Step 6: Final answer
    x = 421.14

Related Problems

Find fourth proportional to 465.11, 697.56 and 140.40
Half scale
Find fourth proportional to 1,860.42, 2,790.24 and 561.60
Double scale
Find fourth proportional to 931.21, 1,396.62 and 281.80
Similar ratio
Find fourth proportional to 1,395.32, 2,092.68 and 421.20
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.