The answer is 11.25 mm.
A diameter of a circle is twice of its radius: d = 2r ⇒ r = d/2
small circle large circle
radius: r1 radius: r2 = ?
diameter: d1 = 15 mm
⇒ r1 = d1/2 = 15/2 mm
Since t<span>he ratio of the radii of two circles is 2:3, we have:
r1 : r2 = 2 : 3
which can also be expressed as:
</span>
<span>
We know that r1 is 7.5, so let's implement it:
</span>
Let's multiply both sides of the by 3r2:
⇒
⇒
A diameter of a circle is twice of its radius: d = 2r ⇒ r = d/2
small circle large circle
radius: r1 radius: r2 = ?
diameter: d1 = 15 mm
⇒ r1 = d1/2 = 15/2 mm
Since t<span>he ratio of the radii of two circles is 2:3, we have:
r1 : r2 = 2 : 3
which can also be expressed as:
</span>
<span>
We know that r1 is 7.5, so let's implement it:
</span>
Let's multiply both sides of the by 3r2:
⇒
⇒