If the diploid chromosome number of typical angiosperm is 36 , what...

The diploid chromosome number of the angiosperm is given as $2n = 36$.

The haploid chromosome number is $n = \dfrac{36}{2} = 18$.

In typical angiosperms, the endosperm is formed by the process of triple fusion, where one haploid male gamete fuses with the diploid secondary nucleus (formed by two haploid polar nuclei).

Therefore, the ploidy level of the endosperm is triploid ($3n$).

The chromosome number in the endosperm will be $3n = 3 \times 18 = 54$.