Matsya Purana — Cosmography of Jambūdvīpa: Varṣas
तस्माद्द्वादशभागेन हेमकूटो ऽपि हीयते हिमवान्विंशभागेन तस्मादेव प्रहीयते अष्टाशीतिसहस्राणि हेमकूटो महागिरिः //
tasmāddvādaśabhāgena hemakūṭo 'pi hīyate himavānviṃśabhāgena tasmādeva prahīyate aṣṭāśītisahasrāṇi hemakūṭo mahāgiriḥ //
Therefore, Hemakūṭa too is diminished by one-twelfth according to that measure; and Himavān, by that very standard, is diminished by one-twentieth. Hemakūṭa—the great mountain—has an extent of eighty-eight thousand.
This verse is not a Pralaya passage; it belongs to cosmographical description, giving proportional rules for how mountain extents are reduced relative to a prior standard.
Directly it does not prescribe dharma; indirectly, such cosmographic knowledge frames pilgrimage, boundary concepts, and the Purāṇic worldview a righteous king is expected to uphold and patronize.
No Vāstu or ritual procedure is stated explicitly; the technical significance is numerical proportion (fractions like 1/12 and 1/20), a style of measurement also echoed in Purāṇic planning and sacred mapping traditions.