The answer of this question is<u> 24 toy trains.</u>
<u>Step-by-step explanation:</u>
Given,
Jerry gave away 15 trains .
Jerry left with 9 trains .
Jerry total brought toy trains = given away toy trains + left with toy trains
Total toy trains = 15 + 9
Total toy trains = 24
<u>Jerry brought a total of 24 toy trains.</u>
Warning: This might be rough...
First draw it out. Label the angles at the corners of the triangle 60 (definition of equilateral triangles). Now draw a line from the center of the circle to the corner, splitting the corner in half. Label this line R and a corner as 30 degrees. No to find the height of this triangle, you do rsin(30). The base of this triangle is 2rcos(30). Now find the area of this mini triangle (rsin(30)*2rcos(30)/2=r/2*rsqrt(3)/2=r^2sqrt(3)/4). Now multiply this by 3 because you have 3 mini triangles... to get...
<span>r^2 3sqrt(3)/4</span>
Answer: 84
<u>Step-by-step explanation:</u>
Set up a proportion as follows: 
Cross multiply: 12x = 7 × 144
Divide by 12: x = 7 × 12
Simplify: x = 84
