$${{\mathtt{91}}}^{\left({\frac{{\mathtt{3}}}{{\mathtt{4}}}}\right)} = {\mathtt{29.463\: \!276\: \!689\: \!625\: \!350\: \!3}}$$
but this is just an approximation. It is an irrational number so it cannot be written exactly as a fraction or as a decimal.
