Answer:
Option B, 40 feet
Explanation:
Kat is painting a triangular stage prop given with lengths of edges as (3x - 4) feet, (x² - 1) feet and (2x² - 15) feet
We have to calculate the perimeter of the triangular prop.
Since perimeter of the prop = sum of lengths of all sides of the triangle
= ( 3x - 4) + ( x² - 1 ) + ( 2x² - 15 )
= 3x - 4 + x² - 1 + 2x² - 15
= ( x² + 2x² ) + 3x - ( 4 + 1 + 15 )
= ( 3x² + 3x - 20 )
If x = 4 then
perimeter = 3 (4)² + 3 (4) - 20
= 3 × 16 + 3 × 4 - 20
= 48 + 12 - 20
= 60 - 20
= 40 feet
Option B, 40 feet is the answer.