Variance and standard deviation from a grouped distribution with the lowest score intervals limits of 50-54 ​

what's that

(5x-1)^2= (5x)^2-2(5x)×1+(1)^2=25x^2-10x+1

if i'm not wrong, i would say that the third angle has (72) because the three sides of all triangles have 180 degrees and if we subtract 180 - 62 - 40 = (72) / but i'm not sure about 40 yd.

pi or 3.14159265359 is an irratinal decimal