Home / 387.72-534.89-221.90

Finding the Fourth Proportional to 387.72, 534.89 and 221.90

Calculator

Solution

The fourth proportional to 387.72, 534.89 and 221.90 is: 306.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    387.72 : 534.89 = 221.90 : x
  2. Step 2: Convert to fraction form
    387.72/534.89 = 221.90/x
  3. Step 3: Cross multiply
    387.72x = 534.89 × 221.90
  4. Step 4: Simplify right side
    387.72x = 118,688.31
  5. Step 5: Solve for x
    x = 118,688.31/387.72
  6. Step 6: Final answer
    x = 306.12

Related Problems

Find fourth proportional to 193.86, 267.44 and 110.95
Half scale
Find fourth proportional to 775.44, 1,069.77 and 443.79
Double scale
Find fourth proportional to 388.72, 536.26 and 222.90
Similar ratio
Find fourth proportional to 581.58, 802.33 and 332.84
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.