Could somebody please help me with question #58 on the June test:
“In the circle with Center D shown below, the length of radius CD is 4cm, the length of BC is 1cm and BC is perpendicular to radius AD at B. When (angle)ADC is measured in degrees, which of the following expressions represents the length, in centimeters, of AC?”
I was hoping to attach a picture, but it doesn’t look like you can here.
Okay, this question might seem very difficult, but just keep this in mind when taking the ACT. Use Logic. That’s right. On the ACT, everything is drawn to scale. So you see the line that measures 1? The Arc AC that they are looking for HAS to be around 1, because logically speaking, it can’t possibly be 10 CM or what not. So I plugged in every answer into my calculator, and when you do that, you notice that question A is the closet to 1. Therefore A is the answer!
Thank you @distractify. I am still curious to know mathematically how to get the right answer if anyone knows…
Distractify’s way of doing that Math problem is the fastest way. The real Math way is very time consuming. Better to do it in less than a minute by guessing and checking the answers than spending over 3-4 minutes trying to get the problem right using real Math.
It doesn’t matter how you get it right, just get it right.
You have the formula to determine the arc length, which is 2piR*( C/360 ), where R is the radius of the circle, C is the central angle of the arc in DEGREES. Plug the measurement in the formula which included angle C = sin^-1( 1/4 ); R=4, so the answer must be A. Sorry if I did not use the English language in the right way, English is not my native language.