Home / 1,428.90-2,143.20-389

Finding the Fourth Proportional to 1,428.90, 2,143.20 and 389

Calculator

Solution

The fourth proportional to 1,428.90, 2,143.20 and 389 is: 583.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,428.90 : 2,143.20 = 389 : x
  2. Step 2: Convert to fraction form
    1,428.90/2,143.20 = 389/x
  3. Step 3: Cross multiply
    1,428.90x = 2,143.20 × 389
  4. Step 4: Simplify right side
    1,428.90x = 833,704.80
  5. Step 5: Solve for x
    x = 833,704.80/1,428.90
  6. Step 6: Final answer
    x = 583.46

Related Problems

Find fourth proportional to 714.45, 1,071.60 and 194.50
Half scale
Find fourth proportional to 2,857.80, 4,286.40 and 778
Double scale
Find fourth proportional to 1,429.90, 2,144.70 and 390
Similar ratio
Find fourth proportional to 2,143.35, 3,214.80 and 583.50
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.