Angles jhi and gjh are inscribed angles. we have that m∠jhi = b and m∠gjh = a by the . angle jhi is an exterior angle of triangle . because the measure of an exterior angle is equal to the sum of the measures of the remote interior angles, m∠jhi = m∠jgi + m∠gjh. by the , b = m∠jgi + a. using the subtraction property, m∠jgi = b – a. therefore, m∠jgi = (b – a) by the distributive property.