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A bar of gold is a prism with volume 165 cm?

Its cross-section is a trapezium with dimensions as shown.

Calculate the length of the gold bar.

A similar bar of gold has a volume of 675.84 cm? Calculate the height of this bar of gold.

A different bar of gold has a volume given by the formula V = h^2 y. Rearrange the formula to make h the subject.

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Answer:

To calculate the length of the gold bar, we need to first calculate the area of the trapezium cross-section, using the formula for the area of a trapezium:

Area = (a + b) x h / 2

where a and b are the lengths of the parallel sides of the trapezium, and h is the height.

From the diagram, we can see that a = 4 cm, b = 10 cm, and h = 7 cm. Substituting these values into the formula, we get:

Area = (4 + 10) x 7 / 2 = 49 cm^2

We can now calculate the length of the gold bar by dividing its volume by its cross-sectional area:

Length = Volume / Area = 165 / 49 = 3.3673 cm (to 4 decimal places)

Therefore, the length of the gold bar is approximately 3.3673 cm.

For the second part of the question, we can use the formula for the volume of a prism to calculate the height of the similar bar of gold:

Volume = Area x Height

where Area is the area of the trapezium cross-section, and Height is the height of the gold bar.

From the given information, we know that Volume = 675.84 cm^3, and we have already calculated Area to be 49 cm^2. Substituting these values into the formula, we get:

675.84 = 49 x Height

Height = 675.84 / 49 = 13.793 cm (to 3 decimal places)

Therefore, the height of the similar bar of gold is approximately 13.793 cm.

For the third part of the question, we need to rearrange the formula V = h^2 y to make h the subject. We can start by dividing both sides by y:

V / y = h^2

Next, we can take the square root of both sides:

sqrt(V / y) = h

Therefore, the formula rearranges to:

h = sqrt(V / y)

This gives us the height of the bar of gold in terms of its volume and the value of y.

Explanation:

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