Question

Two circles of radio 18 cm and 8 cm touches externally.find the length of a direct common tangent to the two circles.

Answer 1

Step-by-step explanation:

radius of first circle, r1=18

as both the circles touch externally,then distance between their centres is

d(oo')=r1+r2=18+8=26cm

now, length of direct common tangent=root d²-(r1-r2)²

=root (26)²-(18-8)²

=root 676-100

=root 576=24cm