Answer: XI = 10.35 mm
Explanation:
Considering the given triangle XIF, to determine XI, we would apply the sine rule. It is expressed as
a/SinA = b/SinB = c/SinC
Where a, b and c are the length of each side of the triangle and angle A, Angle B and angle C are the corresponding angles of the triangle. Likening it to the given triangle, the expression becomes
XI/SinF = XF/SinI = FI/SinX
The sum of the angles in a triangle is 180°. It means that
F + 63 + 52 = 180
F = 180 - (63 + 52)
F = 65°
Therefore
XI/Sin 65 = 9/Sin 52
Cross multiplying, it becomes
XISin52 = 9Sin65
0.788XI = 9 × 0.906
0.788XI = 8.154
XI = 8.154/0.788
XI = 10.35