Home / 499.60-689.34-421.21

Finding the Fourth Proportional to 499.60, 689.34 and 421.21

Calculator

Solution

The fourth proportional to 499.60, 689.34 and 421.21 is: 581.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    499.60 : 689.34 = 421.21 : x
  2. Step 2: Convert to fraction form
    499.60/689.34 = 421.21/x
  3. Step 3: Cross multiply
    499.60x = 689.34 × 421.21
  4. Step 4: Simplify right side
    499.60x = 290,356.90
  5. Step 5: Solve for x
    x = 290,356.90/499.60
  6. Step 6: Final answer
    x = 581.18

Related Problems

Find fourth proportional to 249.80, 344.67 and 210.61
Half scale
Find fourth proportional to 999.20, 1,378.68 and 842.42
Double scale
Find fourth proportional to 500.60, 690.72 and 422.21
Similar ratio
Find fourth proportional to 749.40, 1,034.01 and 631.82
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.