Đáp án:
`a, `
`+, \hat{CBA} = \hat{BAD}`
`+, \hat{BAD } = \hat{ADC}`
`+, \hat{ADC} = \hat{DCB}`
`+, \hat{DCB} = \hat{CBA}`
`b, `
`+, \hat{BMA} = \hat{CMD}`
`+, \hat{BMC} = \hat{AMD}`
`c, `
`+, \hat{CBM} = \hat{MDA}`
`+, \hat{ABM} = \hat{CDM}`
`+, \hat{BCM} = \hat{MAD}`
`+, \hat{DCM} = \hat{BAM}`
`d,` Không có góc