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jasenka [17]
3 years ago
10

EASY TRIG - 15 POINTS

Mathematics
1 answer:
poizon [28]3 years ago
4 0

Answer: The answers are (a) 40 cm and (b) \sin^{-1}\dfrac{23}{62}.


Step-by-step explanation: The calculations are as follows:

(a) See the figure (a). As given in the question, A circle with centre 'O' circumscribes a triangle ABC with BC = 20 cm and ∠BAC = 30°. We need to find the diameter DC of the circle.

Let us draw BD. Now, ∠BAC and ∠BDC are angles on the same arc BC, so we have

∠BAC = ∠BDC = 30°.

Also, ∠CBD = 90°, since it stands on the diameter DC. So, ΔBCD will be a right angled triangle.

We can write

\sin \angle BDC=\dfrac{BC}{DC}\\\\\\ \Rightarrow \sin 30^\circ=\dfrac{20}{DC}\\\\\\\Rightarrow \dfrac{1}{2}=\dfrac{20}{DC}\\\\\\\Rightarrow DC=40.

Thus, the diameter of the circle = 40 cm.


(b) See the figure (b).

As given in the question, A circle with centre 'O'' circumscribes a triangle DEF with EF = 4.6 inches and diameter GF = 12.4 in.. We need to find the angle EDF.

Let us draw GE. Now, ∠EGF and ∠EDF are angles on the same arc EF, so we have

∠EGF = ∠EDF = ?

Also, ∠GEF = 90°, since it stands on the diameter GF. So, ΔGEF will be a right angled triangle.

We can write

\sin \angle EGF=\dfrac{EF}{GF}\\\\\\ \Rightarrow \sin \angle EGF=\dfrac{4.6}{12.4}\\\\\\\Rightarrow \sin \angle EGF=\dfrac{23}{62}\\\\\\\Rightarrow \angle EGF=\sin^{-1}\dfrac{23}{62}.

Thus,

\angle EDF=\angle EGF=\sin^{-1}\dfrac{23}{62}.

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Answer:

B

Step-by-step explanation:

The compound interest formula is A = P (1+r/n)^nt where:

  • P is the starting amount called the principle
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  • t is the number of years

Substitute a value into each variable to solve.

  • P = $147 since 10% of 1,470 is being invested which makes P = 0.10(1470) = 147.
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A = P (1+r/n)^{nt}\\A = 147(1 + \frac{0.035}{12})^{12*25}\\A = 147 ( 1 + 0.002916)^{300}\\A = 147(1.002916)^{300}\\A = 352.19

Repeat this process for each formula.

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valentina_108 [34]

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25.5% of 2553 is 651 students and

0.03% is 8 students.

Now, we divide 651 by 8 to determine the amount of times over basketball was chosen.

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Basketball was chosen 81 times over again compared to soccer.

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