Answer:
36
Step-by-step explanation:
So you know that is it a scale factor of 3 because 15/5 is 3. So you can take ΔDEF and subtract 5 from the perimeter of 12, this gives you 7. Now you know that the sum of the legs equals 7, so you place 3 as a leg and 4 as a leg. Double check you work through the Pythagorean Theorem (a²+b²=c²) 3²+4²=5² 9+16=25 25=25
This checks out so now you can multiply 3 times 3 to get 9 and 4 by 3 to get 12. Now you add 15+12+9= 36
Or you take the scale factor and multiply ΔDEF's perimeter by 3.
