= 4 cm + 4 cm + 4 cm = 12 cm. A square and an equilateral triangle are both examples of regular polygons. Another method for finding the perimeter of a regular polygon is to multiply the number of sides by the length of one side. Let's revisit Examples 3 and 4 using this second method.
Cranial vault expansion is a surgery to correct and reduce the risk of future craniofacial deformities caused by a condition called pediatric craniostenosis. Pediatric craniosynstenosis is the name of a condition where pediatric sutures, which are bony plates in an infantâs head, fuse together too early.
Around 1050 AD, people began using a different kind of vault - the groin vault. It's called a groin vault because the parts meet together in a V, like the V where your legs come together. You make a groin vault by building two barrel vaults that cross each other, so that they make an X. A groin vault can be rounded, as in Romanesque churches, or pointed, as in Gothic churches. The main advantage of the groin vault is that it takes all the weight of the roof and concentrates it on just four points at the corners of each bay (each X).