Ellie wants double her savings of £9000 by investing her money for 18 years what interest rate does she need to look for?
1 answer:
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Answer:
d) 86.2 degrees
x = 86.20°
Attached is the image used in the question;
Step-by-step explanation:
Applying the law of cosine;
Cos C = (a² + b² - c²)/2ab
Where;
Angle C = x
c = 13 ft
b = 9ft
a = 10ft
Substituting into the equation;
Cos x = (10² + 9² - 13²)/(2×10×9)
Cos x = 0.0667
x = cos⁻¹(0.0667)
x = 86.20°
