Answer:
r = 16 units
Step-by-step explanation:
From the figure attached,
AB is the tangent drawn from a point A to the circle C.
BC = r [Radius of the circle]
Length of AC = (18 + r)
AB = 30
By the property of a tangent drawn to a circle,
"Radius of a circle and tangent are perpendicular to each other"
AB ⊥ BC
By applying Pythagoras theorem in ΔABC,
AB² + BC² = AC²
(30)² + r² = (r + 18)²
900 + r² = r² + 36r + 324
36r = 900 - 324
r = 
r = 16 units
Divide both sides by 5:
simplified = 3/7
Hope this helps!
C $1.00
because 1/3 of 15 coins are 5 dimes
15 - 5 = 10 nickels
10 + 5 = 15 coins.
5 dimes= .50 cents
10 nickels= . 50 cents
.50 + .50 = $1.00
$1.00 is C.
*Hope this helped :)