Question

DIRECTIONS: Road the question and select the best respons

A right prism of height 15 cm has bases that are right triangles with legs 5 cm and 12 cm. Find the total
surface area of the prism,
OA 315 cm square
OB, 480 cm square
Oc. 510 cm square
OD. 570 cm square

Please explain how to get the answer

Answer 1

C. 510 cm^2

Explanation:

Well to find TSA or Total Surface Area,

We need to find the area of al the triangles and rectangles.

Let's start with the 2 rectangles facing forwards.

They both have dimensions of 5*15 and 12*15,

75 + 180

= 255 cm ^2

Now let's do the back rectangle which has dimensions of 15 and 13.

15*13 = 195 cm^2

Now we can do the top and bottom triangles,

Since we don't have height we can use the following formula,

`A = √(S(S-a)(S-b)(S-c))`

S is
`S = (1)/(2) (A+B+C)`

S= 15

Now with s we can plug that in,

`A = √(15(15-5)(15-13)(15-12))`

The a b and c are the sides of the triangle.

So let's solve,

15 - 5 = 10

15 - 13 = 2

15 - 12 = 3

10*2*3 = 60

60*15 = 900

`√(900)` = 30 cm^2

Since there is 2 triangles with the same dimensions their areas combined is 60 cm^2

60 + 255 + 195 = 510 cm^2

Thus,

the TSA of the right triangular prism is C. 510 cm^2.

Hope this helps :)

Answer 2

C) 510 square centimetres

Explanation:

The surface area of a prism is given as:

A = bh * pL

where b = base length of the prism = 12 cm

h = base width = 5 cm

p = b + h + c

where c = slant height = 13 cm

L = height of the prism = 15 cm

Therefore, the surface area of the prism is:

A = (12 * 5) + (12 + 5 + 13) * 15

A = 60 + (30 * 15)

A = 60 + 450

A = 510 square centimetres

That is the surface area of the prism.