Mayamatam 26.71

26.71

caturaṃśādhikaṃ bījād dīrghaṃchandamiti smṛtam
ṣaḍaṃśadīrghaṃvipulād vikalpamiti kathyate

longer by four parts than the base, it is remembered as chanda; / longer by six parts than the width, it is called vikalpa;