The lengths of the boards are 6 cm and 8 cm.

The boards make a right angle.
Therefore the string connecting the boards is the hypotenuse of a right triangle (shown n the figure).

By the Pythagorean theorem,
c² = 6² + 8² = 100
c = 10 cm

Answer: c = 10 cm

7 0

4 years ago

What is the area of a circle whose equation is (x-3)² + (y + 1) ² =81?

kupik [55]

Okay, first, given the equation, we need to find out what the radius of the circle is. Let us state the general equation of a circle:

$\frac{(x-x_{1})^2}{r^2}+ \frac{(y-y_{1})_^2}{r^2}=1$

Where $(x_{1}, y_{1})$ is the centre of the circle. In this case, we don't need to know the centre. Just the radius.

Let us start by converting the equation into standard for, which I typed above. Divide both sides by 81.

$\frac{(x-3)^2}{81}+ \frac{(y+1)^2}{81}=1$

Great! We now know the radius of the circle. It is $\sqrt{81}$ because it is the bottom fraction. Now we know that the radius is 9.

So now lets input this into the area of circle formula:

$A=πr^2$

Now we insert our radius.

$A=9^2π$

$=A=81π$

You can convert that into a decimal if you wish.

Hope this helped!

~Cam943, Moderator

4 0

4 years ago