Answer:
Step-by-step explanation:
Surface area = lateral area + 2(area of base)
Lateral area = perimeter of base * height.
Because it is a isosceles right triangle, both sides are equal.
= 72
2 = 72. Divide both sides by 2
= 36. Square both sides.
x = 6.
So the perimeter of the base = 6 + 6 + = 20.485281374239
Lateral area = 20.485281374239 * 7 = 143.397
Area of base is (1/2)base * height.
(1/2)(6)(6) = 18
Using the surface area formula
surface area = 143.397 + 2(18) = 179.4
Answer:56.8 inches
Step-by-step explanation:
For perimeter we must find the lengths of the 2 diagonal sides of the triangle which are the same because it is isosceles.
the triangle is cut directly in half so both halves of the base are 17/2
17/2 = 8.5
solve through pythagoren theorum
altitude^2 + (half of base)^2 = (diagonal length)^2
18^2 + (8.5)^2 = (diagonal length)^2
324 + 72.25 = (diagonal length)^2
396.3 = (diagonal length)^2
= diagonal length
diagonal length = 19.9
diagonal length + diagonal length + base = perimeter
19.9 + 19.9 + 17 = perimeter
56.8 inches = perimeter