Continuing to Payment will take you to apayment page

Purchasing
SparkNotes PLUS
for a group?

Get Annual Plans at a discount when you buy 2 or more!

Price

$24.99$18.74/subscription + tax

Subtotal $37.48 + tax

Save 25%
on 2-49 accounts

Save 30%
on 50-99 accounts

Want 100 or more?
Contact us
for a customized plan.

Continuing to Payment will take you to apayment page

Your Plan

Payment Details

Payment Details

Payment Summary

SparkNotes Plus

You'll be billed after your free trial ends.

7-Day Free Trial

Not Applicable

Renews October 5, 2023September 28, 2023

Discounts (applied to next billing)

DUE NOW

US $0.00

SNPLUSROCKS20 | 20%Discount

This is not a valid promo code.

Discount Code(one code per order)

SparkNotes PLUS
Annual Plan - Group Discount

Qty: 00

SubtotalUS $0,000.00

Discount (00% off)
-US $000.00

TaxUS $XX.XX

DUE NOWUS $1,049.58

SparkNotes Plus subscription is $4.99/month or $24.99/year as selected above. The free trial period is the first 7 days of your subscription. TO CANCEL YOUR SUBSCRIPTION AND AVOID BEING CHARGED, YOU MUST CANCEL BEFORE THE END OF THE FREE TRIAL PERIOD. You may cancel your subscription on your Subscription and Billing page or contact Customer Support at custserv@bn.com. Your subscription will continue automatically once the free trial period is over. Free trial is available to new customers only.

Choose Your Plan

Your Free Trial Starts Now!

For the next 7 days, you'll have access to awesome PLUS stuff like AP English test prep, No Fear Shakespeare translations and audio, a note-taking tool, personalized dashboard, & much more!

Thank You!

You’ve successfully purchased a group discount. Your group members can use the joining link below to redeem their group membership. You'll also receive an email with the link.

No URL

Copy

Members will be prompted to log in or create an account to redeem their group membership.

Thanks for creating a SparkNotes account! Continue to start your free trial.

Please wait while we process your payment

Your PLUS subscription has expired

We’d love to have you back! Renew your subscription to regain access to all of our exclusive, ad-free study tools.

Inequalities are useful in many situations. In particular, they are
useful in geometry when classifying angles.. There
are three types of angles: right angles, acute angles, and
obtuse angles. Right angles have a measure of exactly 90 degrees.
Acute angles have a measure of less than 90 degrees. Obtuse angles
have a measure of greater than 90 degrees (but not more than 180
degrees).

Thus, we can write out inequalities classifying the three types of angles:

x = the measure of angle A in degrees
If x < 90, then A is an acute angle.
If x = 90, then A is a right angle.
If x > 180, then A is an obtuse angle.

Example 1: Angle A measures x degrees. Is A acute if x = 15? If x = 65? If x = 90? If x = 135?

15 < 90 ? Yes. A is acute if x = 15.
65 < 90 ? Yes. A is acute if x = 65.
90 < 90 ? No. A is not acute if x = 90.
135 < 90 ? No. A is not acute if x = 135.

Example 2: If angle A measures 2x - 5 degrees, for which of the following
values of x is A obtuse? {25, 45, 65, 85}

2(25) - 5 > 90 ? No.
2(45) - 5 > 90 ? No.
2(65) - 5 > 90 ? Yes.
2(85) - 5 > 90 ? Yes.
Thus, A is obtuse for x = {65, 85}.

Example 3: Which angle is right? Acute? Obtuse?

Angle A is acute, angle B is right, and angle C is obtuse.