how can you copy a angle using a straightedge, a compass, and a pencil, give step by step instructions

2 answers:

8 0

Start with a angle BAC that we will copy.
1. Make a point P that will be the vertex of the new angle.
2. From P, draw a ray PQ. This will become one side of the new angle.

This ray can go off in any direction.
It does not have to be parallel to anything else.
It does not have to be the same length as AC or AB.

3. Place the compasses on point A, set to any convenient width.
4. Draw an arc across both sides of the angle, creating the points J and K as shown.
5. Without changing the compasses' width, place the compasses' point on P and draw a similar arc there, creating point M as shown.
6. Set the compasses on K and adjust its width to point J.
7. Without changing the compasses' width, move the compasses to M and draw an arc across the first one, creating point L where they cross.
8. Draw a ray PR from P through L and onwards a little further. The exact length is not important.
Done. The angle ∠RPQ is congruent (equal in measure) to angle ∠BAC.

MissTica2 years ago

6 0

Answer:

Step-by-step explanation: Draw a working line, l, with point B on it.

Open your compass to any radius r, and construct arc (A, r) intersecting the two sides of angle A at points S and T.

Construct arc (B, r) intersecting line l at some point V.

Construct arc (S, ST).

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A building has an entry the shape of a parabolic arch 84 ft high and 42 ft wide at the base, as shown below. A parabola opening

lara [203]

Answer:

Step-by-step explanation:

Because of the nature of the information we are given, we have no choice but to use the equation

$y=a(x-h)^2+k$

and solve for a.

We know by the info that the vertex is (0, 84). We also know that if the vertex is at the origin, and that the base is 42 feet wide, it spans 21 feet to the right of the origin and 21 feet to the left of the origin. That means that we have 2 coordinates from which we need to pick one for our x and y in the equation. I don't like negatives, so I am going to choose the coordinate (21, 0) as x and y. Because this parabola opens upside down, as archways of door openings do, our "a" value better come out algebraically as a negative. Let's see...From the vertex we have that h = 0 and k = 84. So filling in:

$0=a(21-0)^2+84$ and simplifying a bit: