Answer:
57
Step-by-step explanation:
If m<HIC is 99, so m<EIC is 81 (bc m<HIC + m<EIC = 180)
so m<GIH is also 81
m<HGI is the same with m<DGB =42
so:
42 + 81 + x =180
x = 180 - 42 - 81
x = 57
