Question

cho tu giac abcd biet goc a: goc b: goc c: goc d =4:3:2:1

a) tinh cac goc cua tu giac abcd

b) cac tia phan giac cua goc c va goc d cat nhau tai e. cac duong phan giac cua goc ngoai tai ca dinh c va d cat nhau tai f. tinh goc ced va goc cfd

Answer 1

a) Ta có: \(\frac{\widehat{A}}{4}=\frac{\widehat{B}}{3}=\frac{\widehat{C}}{2}=\frac{\widehat{D}}{1}\)

Áp dụng t/c dãy tỉ số bằng nhau ta được:

\(\frac{\widehat{A}}{4}=\frac{\widehat{B}}{3}=\frac{\widehat{C}}{2}=\frac{\widehat{D}}{1}=\frac{\widehat{A}+\widehat{B}+\widehat{C}+\widehat{D}}{4+3+2+1}=\frac{360}{10}=36\)

\(\Rightarrow\widehat{A}=144^0;\widehat{B}=108^0;\widehat{C}=72^0;\widehat{D}=36^0\)