Can anybody HELP PLEASE

Mathematics

1 answer:

REY [17]3 years ago

3 0

Answer:

use mathpapa its a free website

Step-by-step explanation:

it dose all kinds of math that could help alot

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1)a chord of length 18cm midway the radius of a circle. calculate the radius of the circle correct to 1d.p. 2)if two parallel ch

kykrilka [37]

Part 1:

Given that the length of the chord is 18 cm and the chord is midway the radius of the circle.

Thus, half the angle formed by the chord at the centre of the circle is given by:

$\cos\theta=\frac{\left( \frac{1}{2} r\right)}{r}= \frac{1}{2} \\ \\ \Rightarrow\theta=\cos^{-1}\left( \frac{1}{2} \right)=60^o$

Now,

$\sin60^o= \frac{9}{r} \\ \\ \Rightarrow r= \frac{9}{\sin60^o} =10.392$

Therefore, the radius of the circle is 10.4 cm to 1 d.p.

Part 2I:

Given that the radius of the circle is 10 cm and the length of chord AB is 8 cm. Thus, half the length of the chord is 4cm. Let the distance of the mid-point O to /AB/ be x and half the angle formed by the chord at the centre of the circle be θ, then

$\sin\theta= \frac{4}{10} = \frac{2}{5} \\ \\ \theta=\sin^{-1}\left( \frac{2}{5} \right)=23.6^o$

Now,

$\cos23.6^o= \frac{x}{10} \\ \\ \Rightarrow x=10\cos23.6^o=9.165\approx9.2cm$

Part 2II:

Given that the radius of the circle is 10cm and the angle distended is 80 degrees. Let half the length of chord CD be y, then:

$\sin40^o= \frac{y}{10} \\ \\ \\ \Rightarrow y=10\sin40^o=6.428$

Thus, the length of chord CD = 2(6.428) = 12.856 which is approximately 12.9 cm.

3 0

3 years ago

A family of 17 are trying to get back to their island for Christmas when disaster strikes – their ship hits a rock and will sink

wlad13 [49]

Answer: 13

Althoug each round trip takes 9 minutes and can carry 5 people on the boat, you can not just divide the 20 minutes time by 9 and multiply by 5 to find the number of people that are saved without getting wet.

First trip:

5 people take the boat to the island but only 4 can stay, because one has to return with the boat to the ship to rescue other 4 people.

So, when 9 minutes have passed, 4 people are safe on the island and the boat is again by the ship.

Second trip:

In the second trip, other 4 people are rescued,along with "sailor" who returned in the boat to rescue them.

When it has passed 18 minutes, the boat is next to the ship agin to carry other 4 people before the boat sinks.

This is the last trip before the boat sinks. So, the total number of passengers rescued is 4 + 4 + 5 = 13

8 0

3 years ago

Read 2 more answers

Susan has $65 to spend at the fair. She spends $10 an admission and $35 on food at the fair. She wants to play a game that costs

abruzzese [7]

Answer: 26.6666666667 or 26.7

Step-by-step explanation:

65=10+35+.75x

65=45+.75x

20=.75x

26.7 = x

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