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Answer:
15
Step-by-step explanation:
(whole secant) x (external part) = (tangent)^2
(5+x) * 5 = 10^2
Distribute
25 +5x = 100
Subtract 25 from each side
25-25 +5x = 100-25
5x= 75
Divide by 5
5x/5 = 75/5
x = 15
Remark
A cube has six sides, all of them equal. The formula for 1 side is s^2. The formula for all six = 6s^2.
Step One
Find the surface area of the larger cube.
Area = 6 *s^2
s = 15
Area = 6 *15^2
Area = 6 * 225
Area = 1350
Step Two
Find the area of the smaller cube
Area = 6s^2
Area = 6 * 12^2
Area = 6 * 144
Area = 864
Step Three
Find the difference
Area1 - Area2 = difference
1350 - 864 = 486
The difference is area = 486 units^2 <<<<< Answer
There is a slightly shorter way. Take out the common factor of 6
Difference = 6 * (15^2 - 12^2)
Difference = 6 * (225 - 144)
Difference = 6 * (81)
Difference = 486
To find the area of a rhombus, the formula is d1(d2)/2
d1 is 4+4 or 8
d2 is 7+10 or 17
17(8)=136
136/2=68
It is d, -8.-5. I did it on paper
