Can you calculate the volume of an n-dimensional hypersphere?

You may ask "what is an n-dimensional hypersphere?". It is a generalisation of a sphere to n dimensions. It is not hard to imagine if you think of a co-ordinate system in n dimensions. It is the set of points which is less than a certain distance (the radius) from a point (the centre) in n-dimensional space. If you have a set of Euclidean co-ordinates {x_i}, for i=1 to n, then the distance is defined by Pythagoras, so we have the equation of the "surface" which is -mathformula not MarkupType-
Fatal error: Uncaught Error: Call to undefined method mathformula::makeTypeDef() in /var/www/vhosts/ent.storkey.uk/html/inc/reporting2.php:365 Stack trace: #0 /var/www/vhosts/ent.storkey.uk/html/inc/dynaPage.php(189): echo_value('volhypersphere', 'content', Array) #1 /var/www/vhosts/ent.storkey.uk/html/inc/dynaPage.php(742): dynaPage->echo_value('content') #2 /var/www/vhosts/ent.storkey.uk/html/inc/dynaPage.php(179): mainPanel->write('main-panel') #3 /var/www/vhosts/ent.storkey.uk/html/index.php(21): dynaPage->write() #4 {main} thrown in /var/www/vhosts/ent.storkey.uk/html/inc/reporting2.php on line 365