80
8 x 10
2 x 4 x 5 x 2
2 x 2 x 2 x 2 x 5 <===
The correct answer is x=18
7.5cm
lets take point K represent lenght from M to perimeter of circle.
r is radius
KM= r-OM= r-4.5cm
now lets draw line from O to A (OA)
we get triangle.
hypotenuse is OA and it equals r(radius)
ab=12 cm. so another side of the triangle (AM) is 12/2=6cm. and the last side of the triangle is 4.5(OM)
use pythaghorean theorem
squares of sides added = square of hypotenuse
20.25+36=r^2(our hypotenuse is radius)
56.25=r^2
r=√56.25=7.5cm
