Please help me. The answer in the booklet says it’s R=3, but I need working out because I don’t get it.

Answer:
3.
Step-by-step explanation:
R = √[(2)^2 + (√5)^2]
= √(4 + 5)
= √9
= 3.
Answer:
3
Step-by-step explanation:
[tex]R =\sqrt{a^{2}+b^{2}}\\\\= \sqrt{2^{2}+(\sqrt{5})^{2}}\\\\= \sqrt{4+5}\\\\=\sqrt{9}\\\\= \sqrt{3*3}\\\\= 3[/tex]
Hint: (√5)² = [tex]\sqrt{5}*\sqrt{5} = \sqrt{5*5}=5[/tex]