Answer:
∡B = 60°
Step-by-step explanation:
find BC using Pythagorean Theorem:
5² + BC² = 10²
25 + BC² = 100
BC² = 75
BC = [tex]\sqrt{75}[/tex]
BC = [tex]\sqrt{25}[/tex][tex]\sqrt{3}[/tex] which is 5[tex]\sqrt{3}[/tex]
this indicates that ∡B must be 60° because the ratio of sides in a 30-60-90 triangle are 1 : [tex]\sqrt{3}[/tex] : 2
