Answer:
4
Step-by-step explanation:
You can use the Pythagorean theorem to find the length of the unknown side.
For that, let the unknown side be x.
Let us solve now.
2² + x² = ( 2√5)²
4 + x² = 2√5 × 2√5
4 + x² = 2 × 2 × √5 × √5
4 + x² = 4 × 5
4 + x² = 20
x² = 20 - 4
x² = 16
x = √16
x = 4
Hope this helps you :-)
Let me know if you have any other questions :-)
