Respuesta :
Answer:
See the attached figure which represents the problem.
Angles GJH and JHI are inscribed angles
Given: ∠GJH = 0.5a and ∠JHI = 0.5b ⇒ inscribed angle theorem
So, the angle JHI is an exterior angle of ΔGJH
AS, the measure of the exterior angle is equal to the sum of the sum of the remote interior angles
So, ∠JHI = ∠GJH + ∠JGI ⇒ by substitution property
∴ 0.5 b = 0.5a + ∠JGI
∴ ∠JGI = 0.5b - 0.5a ⇒ take 0.5 as a common
∠JGI = 0.5 ( b - a ) ⇒ by distributive property.
So, m∠JGI = One-half(b – a)

Answer:
see the explanation
Step-by-step explanation:
The picture of the question in the attached figure
we know that
The measure of the exterior angle is the semi-difference of the arches it covers.
In this problem
m∠JGI is an exterior angle
so
[tex]m\angle JGI=\frac{1}{2}[arc\ JI-arc\ FH][/tex]
we have
[tex]arc\ JI=b^o\\arc\ FH=a^o[/tex]
substitute the given values
[tex]m\angle JGI=\frac{1}{2}(b-a)^o[/tex]
Prove
Remember that
In any triangle the measure of an exterior angle is equal to the sum of the measures of the remote interior angles
so
In the triangle GJH
[tex]m\angle JHI=m\angle JGI+m\ angle GJH[/tex] ----> equation A
Remember that
The inscribed angle is half that of the arc it comprises.
so
[tex]m\angle JHI=\frac{b}{2}[/tex]
[tex]m\angle GJH=\frac{a}{2}[/tex]
substitute in the equation A
[tex]\frac{b}{2}=m\angle JGI+\frac{a}{2}[/tex]
Using the subtraction property
[tex]m\angle JGI=\frac{b}{2}-\frac{a}{2}[/tex]
simplify
[tex]m\angle JGI=\frac{1}{2}(b-a)^o[/tex] ----> proved
