Answer:
D:456.2 units²
Step-by-step explanation:
<u>Step 1: Area of all 4 sides of cuboid</u>
<em>Area of rectangle = 4 x length x breadth</em>
<em>Area of rectangle = 4 x 10 x 5</em>
Area of rectangle = 200
<u>Step 2: Calculate bottom of cuboid</u>
<em>Area = length x breadth </em>
<em>Area = 10 x 10</em>
Area = 100
<u>Step 3: Calculate slant height of pyramid</u>
<em>c² = a² + b²</em>
<em>c² is hypotenuse</em>
<em>a² is the base which is half of w (10/2 = 5)</em>
<em>b² is y which is 6</em>
<em>c² = a² + b²</em>
<em>c² = 5² + 6²</em>
<em>c = √61</em>
<u>Step 4: Calculate area of one face of the pyramid</u>
<em>Area of triangle = 1/2 x base x height</em>
<em>Area of triangle = 1/2 x 10 x √61</em>
<em>Area of triangle = 5√61</em>
<u>Step 5: Calculate areas of all 4 faces of the pyramid </u>
4 x 5√61 = 20√61
<u>Step 6: Calculate the total surface area</u>
Total surface area = 200 + 100 + 20√61
Total surface area = 456.2
The surface area of the figure is 456.2 units²
Option D is correct.
!!
