### SAT数学：圆的方程 1

2019-08-29 SAT-数学 阅读

# SAT Question 11 Article Rank: Medium 难度： 中等 Topic: Algebra, Geometry, Equation of a Circle 话题：代数，几何，圆的方程

Below is a question from a recent SAT exam. It is a non-calculator question that would typically take a student 1-2 minutes to complete.

A circle in the xy-plane has center (5, 7) and radius 2. Which of the following is an equation of the circle?
xy平面上有一个圆心为(5,7)，半径为2的圆，下面哪个是此圆的方程? To begin, we will recall the formula for the equation of a circle  Where a is the x-coordinate for the centre of the circle, b is the y-coordinate of the centre of the circle, and r is the radius.

We are told in the question that the circle has a radius of 2. Therefore,    Our equation now looks like this.  Next, we substitute a and b for the values given as the circle's centre.

a = 5, b = 7    • 地址：401-5811 Cooney Rd, Richmond, BC
• 地址：3030-8171 Ackroyd Rd, Richmond, BC
• 客服热线：604-370-0579 & 604-370-2569
• 联系邮箱：service@forbest.com

• 地址：江苏省无锡市梁溪区清扬路268号三楼
• 客服热线：181-1861-8855

• 官方公众号
• 加拿大官方客服
• 中国官方客服 