Answer:
BR ≈ 49.0
Step-by-step explanation:
Use cosine:
[tex]cosine=\dfrac{adjacent}{hypotenuse}[/tex]
We have
[tex]adjacent=42\\hypotenuse=BR\\\alpha=31^o[/tex]
[tex]\cos31^o\approx0.8572[/tex]
Substitute:
[tex]\dfrac{42}{BR}=0.8572[/tex]
[tex]\dfrac{42}{BR}=\dfrac{8,572}{10,000}[/tex] cross multiply
[tex]8,572BR=420,000[/tex] divide both sides by 8,572
[tex]BR=\dfrac{420,000}{8,572}[/tex]
[tex]BR\approx49.0[/tex]
