*see attachment for the figure
Answer:
x = 17 cm
Explanation:
Total surface area of triangular prism = bh + L(s1 + s2 + s3)
Where,
Total surface area = 456 cm²
b = 8 cm
h = 6 cm
s1 = √(8² + 6²) = 10 cm (pythagorean theorem)
s2 = 8 cm
s3 = 6 cm
L = x
Plug in the values
465 = 8*6 + x(10 + 8 + 6)
465 = 48 + x(24)
465 - 48 = 24x
417 = 24x
417/24 = x
17.375 = x
x = 17 cm (approximated)