Evaluate Without Using a Calculator by Using Ratios in a Reference

question 487

Multiple Choice

Evaluate without using a calculator by using ratios in a reference triangle.
- $\cos \left( - \frac { 5 \pi } { 4 } \right)$

• A) \(\frac { 1 } { 2 }\)
• B) \(- \frac { \sqrt { 3 } } { 2 }\)
• C) \(\frac { \sqrt { 3 } } { 2 }\)
• D) \(- \frac { \sqrt { 2 } } { 2 }\)

---

Definitions:

Army Corps of Engineers

A federal agency under the Department of Defense that provides public engineering, design, and construction management services, often related to water resources.

National Priority List

A list in the United States that identifies sites that are priorities for investigation and cleanup because they release or threaten to release hazardous substances.

Comprehensive Environmental Response, Compensation, and Liability Act

A U.S. federal law, established to clean up sites contaminated with hazardous substances and pollutants.

Alpha Particle

A type of ionizing radiation consisting of two protons and two neutrons, emitted from the nucleus of an atom during radioactive decay.