Home / 399.69-551.21-281.70

Finding the Fourth Proportional to 399.69, 551.21 and 281.70

Calculator

Solution

The fourth proportional to 399.69, 551.21 and 281.70 is: 388.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    399.69 : 551.21 = 281.70 : x
  2. Step 2: Convert to fraction form
    399.69/551.21 = 281.70/x
  3. Step 3: Cross multiply
    399.69x = 551.21 × 281.70
  4. Step 4: Simplify right side
    399.69x = 155,274.45
  5. Step 5: Solve for x
    x = 155,274.45/399.69
  6. Step 6: Final answer
    x = 388.49

Related Problems

Find fourth proportional to 199.85, 275.60 and 140.85
Half scale
Find fourth proportional to 799.38, 1,102.41 and 563.40
Double scale
Find fourth proportional to 400.69, 552.58 and 282.70
Similar ratio
Find fourth proportional to 599.54, 826.81 and 422.55
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.