Manasara 45.48

45.48

śeṣaṃ masūrakaṃ vāpi samādhiṣṭhānatuṅgakam
utsedharavibhāge tu janmatuṅgaṃ śivāṃśakam

the remainder is the base platform (masūraka), or equal to the height of the plinth base (adhiṣṭhāna). / When the height is divided into twelve parts, the plinth (janman) height is one part;