Question

1. starting with 2 marked points, a and b, precisely describe the straightedge and compass moves required to construct the quadrilateral acbd in this diagram.

Explanation:

Step1: Set compass radius

Set the compass radius to the length of segment $AB$. Place the compass at point $A$.

Step2: Draw first circle

Draw a circle centered at point $A$.

Step3: Draw second circle

Without changing the compass - radius, place the compass at point $B$ and draw a circle. Let the two intersection points of the circles be $C$ and $D$.

Step4: Connect points with straightedge

Use a straightedge to connect points $A$ to $C$, $C$ to $B$, $B$ to $D$, and $D$ to $A$.

Answer:

1. Set compass radius to $AB$, center at $A$ and draw a circle.
2. Keep compass radius, center at $B$ and draw a circle.
3. Use straightedge to connect $A - C$, $C - B$, $B - D$, $D - A$.