Here a right angled triangle given. We know that one angle of a right angled triangle is 90°.
As the sum of three angles of a triangle is 180°, so we can say the sum of other two angles of a right angled triangle is (180-90)° = 90°.
Here in the figure the other two angles given
and
. Sum of these two angles is 90°.
So we can write the equation as,

We have to remove the parenthesis now.

Now we will add the like terms. Here x and 2x are like terms. By adding them we will get,

To solve it for x, now we have to move 15 to the other side by subtracting it from both sides.



Now to get x, we have to move 3 to the other side, by dividing it to both sides.



We have got the required value of x.
The solution is x= 25.
Answer:
C. √2 - 1
Step-by-step explanation:
If we draw a square from the center of the large circle to the center of one of the small circles, we can see that the sides of the square are equal to the radius of the small circle (see attached diagram)
Let r = the radius of the small circle
Using Pythagoras' Theorem 
(where a and b are the legs, and c is the hypotenuse, of a right triangle)
to find the diagonal of the square:



So the diagonal of the square = 
We are told that the radius of the large circle is 1:
⇒ Diagonal of square + r = 1





Using the quadratic formula to calculate r:




As distance is positive,
only
Answer:
x= 14
Step-by-step explanation:
First (and only) we subtract 17 from both sides :
17 + x - 17 = 31 - 17
x = 31 - 17
x = 14
Hope this helped and have a good day
Answer:
lateral area = 2320 m²
Step-by-step explanation:
The question wants us to calculate the lateral area of a square base pyramid. The square base pyramid has a side of 40 meters.The height is 21 meters.
Half of the square base is 40/2 = 20 meters . With the height it forms a right angle triangle. The hypotenuse side is the slant height of the pyramid.
Using Pythagoras's theorem
c² = a² + b²
c² = 20² + 21²
c² = 400 + 441
c² = 841
square root both sides
c = √841
c = 29 meters
The slant height of the pyramid is 29 meters.
The pyramid has four sided triangle. The lateral area is 4 multiply by the area of one triangle.
area of triangle = 1/2 × base × height
base = 40 meters
height = 29 meters
area = 1/2 × 40 × 29
area = 580
area of one triangle = 580 m²
Lateral area = 4(580)
lateral area = 2320 m²