What is the surface area of the cube? A. 243 cm2 B. 364.5 cm2
C. 486 cm2 D. 729 cm2
(first answer gets

c. 486cm²

Step-by-step explanation:

Given parameters:

 Length  = 9cm

 Width = 9cm

 Breadth  = 9cm

Unknown:

Surface area of the cube  = ?

Solution:

 The surface area of a cube is given as:

    Surface area  = 6l²

l is the length;

 For a cube all the sides are equal

   Surface area = 6 x 9²  = 486cm²

answer: both chords and diameters have two endpoints on a circle. diameters must intersect the center of a circle.

< xcy ≅ < xby

step-by-step explanation:

in δcax and δbax,

so, δcax ≅ δbax (side-angle-side or sas)

since δcax ≅ δbax, we can conclude < acx ≅ < abx

in δacy and δaby,

so, δacy ≅ δaby (side-angle-side or sas)

since δacy ≅ δaby, we can conclude < acy ≅ < aby

now,

< acy ≅ < aby

=> < acx + < xcy ≅ < abx + < xby

=> < acx + < xcy ≅ < acx + < xby   (since < acx ≅ < abx already proved above)

subtracting < acx from both sides, we get

< acx + < xcy -< acx ≅ < acx + < xby -< acx

cancelling out < acx and -< acx from both sides, we get

< xcy ≅ < xby (proved)