Home / 289.80-431.49-288.20

Finding the Fourth Proportional to 289.80, 431.49 and 288.20

Calculator

Solution

The fourth proportional to 289.80, 431.49 and 288.20 is: 429.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    289.80 : 431.49 = 288.20 : x
  2. Step 2: Convert to fraction form
    289.80/431.49 = 288.20/x
  3. Step 3: Cross multiply
    289.80x = 431.49 × 288.20
  4. Step 4: Simplify right side
    289.80x = 124,355.42
  5. Step 5: Solve for x
    x = 124,355.42/289.80
  6. Step 6: Final answer
    x = 429.11

Related Problems

Find fourth proportional to 144.90, 215.75 and 144.10
Half scale
Find fourth proportional to 579.60, 862.98 and 576.40
Double scale
Find fourth proportional to 290.80, 432.98 and 289.20
Similar ratio
Find fourth proportional to 434.70, 647.24 and 432.30
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.