Perimeter = namely the length of outside bordering,
well, this is a PENTAgon, or PENTA=5 or namely 5 sides, is regular so each side is the same length, so we have a polygon with 5 sides each measuring 40cm, well, its perimeter is just 40+40+40+40+40 = 200.
Hello :
<span>a point on the y-axis is : P( 0, y)
</span>PA = PB or PA² = PB².... A(7, -7) B(1,1)
(7-0)²+(-7-y)² = (1-0)² + (1-y)²
49+49+14y+y² = 1+1-2y+y²
16y = - 96
y= - 6