Question

Given right triangle ABCABC with altitude \overline{BD} BD drawn to hypotenuse ACAC. If BC=10BC=10 and DC=5,DC=5, what is the length of \overline{AC}? AC ?

Answer 1

Answer: $\overline{AC}=$ 12.5

Step-by-step explanation: The triangle ABC and its altitude $\overline{BD}$ is represented in the figure below.

Altitude is a segment of line that link a vertex and the opposite side, forming a right angle.

So, because of $\overline{BD}$, now we have two similar triangles, which means that ratios of corresponding sides are equal:

$\frac{\overline{BD}}{\overline{BC}} =\frac{\overline{AD}}{\overline{BD}}$

$\overline{BD}^{2}=\overline{BC}.\overline{AD}$ (1)

This is always true for a right triangle and a altitude drawn to the hypotenuse.

Triangle BDC is also right triangle. So, we can use Pythagorean theorem to determine the missing side.

$\overline{BC}^{2}=\overline{CD}^{2}+\overline{BD}^{2}$

$\overline{BD}^{2}=\overline{BC}^{2}-\overline{CD}^{2}$ (2)

Substituting (2) into (1):

$\overline{BC}^{2}-\overline{CD}^{2}=\overline{BC}.\overline{AD}$

We want to find f, so:

$\overline{AD}=\frac{\overline{BC}^{2}-\overline{CD}^{2}}{\overline{BC}}$

$f=\frac{10^{2}-5^{2}}{10}$

f = 7.5

The length of $\overline{AC}$ is

$\overline{AC}=f+5$

$\overline{AC}=7.5+5$

$\overline{AC}=12.5$

The length of the hypotenuse of triangle ABC is 12.5 units.

Answer 2

Answer:

x = 20

Step-by-step explanation: