Pls help I forgot what a polygon is

What is the area of the triangle 10 13 12

The length of a rectangle is x times the square root of 100. the width is one-half y more than three-halves x. given that the area of the rectangle is 125 cm2, which equation could represent the rectangle in terms of x and y? a) 5xy − 15x = 125 b) 5xy + 15x = 125 c) 15x2 − 5xy = 125 d) 15x2 + 5xy = 125

The average length of a king cobra is 3.7 m. the record length is 1.88 m longer than the average. how long is the record holder?