# Which of the following equations describes a circle with radius 10 that passes through the origin when graphed in the xy-plane?

Which of the following equations describes a circle with radius 10 that passes through the origin when graphed in the xy-plane?

A) (x – 5)² + (y+5)² = 10

B) (x – 5)² + (y+5)² = 100

C) (x – 10)² + (y+10)² = 10

D) (x – 5√2)² + (y+5√2)² = 100

Clearly, A) is out because that one does not have a radius of 10. What is the most time-efficient way to solve this? Sketch and eyeball?

# In a circle with area of 120 to 124 sq inches…

In a circle with area of 120 to 124 sq inches, the area of the sector formed by an angle is between 20 and 21 sq inches. What is one possible integer value of the angle?

I came up with a low value of 60 (if area of circle is on the lowest end, 120 sq inches, and area of the sector is also on the low end, 20 inches). If both those areas are on the highest end, then I came up with 60 again. But answer is supposed to be 59 ≤ x ≤ 63. Does this make sense, and if so, can you explain it?

# If the circumference of the circle with center O is 12π and angle AOB is 60 degree , what is the length of minor arc AB?

60° is 1/6 of the circle (which has 360° of arc in total), so the length of the minor arc will be 1/6 of the circumference. 1/6 of 12π is 2π. from Tumblr https://ift.tt/2JsMj92

# In a circle with center O, the length of radius OB is 5. If the length of chord CD is 8, and if line CD perpendicular to line OB, then sin angle OCD =

Start by drawing it! Note that OC = 5 and OD = 5 because both of those are also radii. Note also that because chord CD is perpendicular to OB, it’s bisected by OB. In other words, it’s split into 2 segments each measuring 4.   Things are really coming together! Because we know our Pythagorean (more…)

# What is the area of a circle that is inscribed in a square of area 2

First, a circle inscribed in a square looks like this: If that square has an area of 2, that means each of its sides has a length of √2. And THAT means that the radius of the circle is √2/2. The area of a circle is πr^2. Plug √2/2 in for r and you’ve got your (more…)

# Test 7 Section 4 #34

Test 7 Section 4 #34

# Test 4 Section 4 Number 24

Test 4 Section 4 Number 24

# Test 7 Section 3 #18 please

Test 7 Section 3 #18 please

# Practice question for Circles, Radians, and a Little More Trigonometry, #5, p. 272, 4th Ed.

Practice question for Circles, Radians, and a Little More Trigonometry, #5, p. 272, 4th Ed.

# Test 8 Section 3 #20

Test 8 Section 3 #20

# Can you explain #9 on pg 273 in the PWN book please?

Can you explain #9 on pg 273 in the PWN book please?

# Hi Mike, Can you please do practise test 7, section 4, question 29 (Whats the fastest way to do it which doesn’t involve using the distance formula for every answer option)

Hi Mike,

Can you please do practise test 7, section 4, question 29 (Whats the fastest way to do it which doesn’t involve using the distance formula for every answer option)

# Hi Mike, Can you tell me how to do #27 (Section 4, Practice Test 6).

Hi Mike,

Can you tell me how to do #27 (Section 4, Practice Test 6). I know how to do it by completing the square but was wondering if there is an easier way.

thanks!
Rachel

# Test 4, Section 4, Number 36 (Calculator Section)

Test 4, Section 4, Number 36 (Calculator Section)

# Test 3 Section 4 #34

Test 3 Section 4 #34