You can put it in a TI84 calculator and find the answer.
Answer:
x = √30
Step-by-step explanation:
From small triangle BDC:
using Pythagorean theorem
CB² = BD² + DC²
x² = BD² + 3²
Fron triangles BDC and ADB.
ΔBDC has long leg BD and short leg DC.
ΔADB has long leg AD and shirt leg BD.
AD : BD = BD : DC
7 : BD = BD : 3
7*3 = BD*BD
BD² = 7*3 = 21
x² = BD² + 3² = 21+9 = 30
x² = 30
x = √30
If the points are
collinear, then that would mean that the points lie on the same line when joined
to each other. In order to confirm this, the distances between the points must
sum up to the length of the line.<span>
AB + BC = AC
7 + 4 ? 9
11 ≠ 9
<span>Since they do not sum up, therefore, the points are not
collinear.</span></span>
So you have
8 digits (number available) to form
3 digit numbers (number selected).
Using the formula

where a is the number of available digits, P is the permutation function and c is the number of digits to be selected.
The number of three digit numbers that can be formed =

=
336 <span>
O R</span>By using the formula

where a is the number of available digits and c is the number of digits to be selected.<span>
</span>⇒

<span>
</span>⇒

<span>
</span>⇒ Permutation =
336<span>
</span>