Question

ΔRST and ΔXYZ are equilateral triangles. The ratio of the perimeter of ΔRST to the perimeter of ΔXYZ is 1 to 3. The area of ΔRST is 10.825 square inches. What is the area of ΔXYZ? (round to nearest tenth)

Answer 1

For the scale factor of 1:3. Use ratio and proportion to solve for the area of the triangle. 

area of triangle RST/ area of triangle XYZ = (1/3)^2
where
area of traianlge RST = 10.825 inch^2
Area of triangle XYZ= Area of triangle RST x (3)^2
Substitute the given values=97.4 inch^2

Answer 2

I worked it out and checked to get D- 97.4 :)