Circles & Arcs Flashcards
7 cards from real Geometry practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Circles & Arcs flashcards as text
A chord is 8 units long and is 3 units from the center. What is the radius (to nearest whole)?
Answer: 5
Half-chord 4, distance 3: r = √(4² + 3²) = √25 = 5.
Two chords intersect inside a circle. One is divided into segments 3 and 8; the other into 4 and x. Find x.
Answer: 6
By the intersecting chords rule, 3×8 = 4×x, so x = 24/4 = 6.
The circumference of a circle is 31.4. Using π ≈ 3.14, what is the diameter?
Answer: 10
C = πd, so d = 31.4 / 3.14 = 10.
A tangent line meets a radius at the point of tangency at an angle of:
Answer: 90°
A radius is always perpendicular to a tangent at the point of contact.
The arc opposite a 40° inscribed angle measures:
Answer: 80°
The intercepted arc is twice the inscribed angle: 2 × 40° = 80°.
In a circle of radius 10, a sector has area 25π. What is its central angle?
Answer: 90°
25π = (θ/360)π(100), so θ/360 = 1/4, giving θ = 90°.
The longest chord in any circle is called the:
Answer: Diameter
The diameter passes through the center and is the longest chord.