Three solid shapes A, B and C are similar - Edexcel - GCSE Maths - Question 16 - 2018 - Paper 1
Question 16
Three solid shapes A, B and C are similar.
The surface area of shape A is 4 cm²
The surface area of shape B is 25 cm²
The ratio of the volume of shape B to the vol... show full transcript
Worked Solution & Example Answer:Three solid shapes A, B and C are similar - Edexcel - GCSE Maths - Question 16 - 2018 - Paper 1
Step 1
Find the ratio of lengths for shapes A and B
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Answer
To find the ratio of lengths we use the relationship between surface area and lengths in similar shapes. The surface area ratio is given by:
SurfaceAreaofBSurfaceAreaofA=254
The ratio of surface areas is proportional to the square of the ratio of corresponding lengths. Therefore, if the ratio of lengths is ( k ), we have:
254=k2
Solving for k gives:
k=254=52
Step 2
Find the ratio of lengths for shapes B and C
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Answer
Given the volume ratio of shape B to shape C as 27:64, we can derive the ratio of lengths. The volume ratio is proportional to the cube of the ratio of corresponding lengths. If the ratio of lengths is ( m ), we have:
VolumeofCVolumeofB=6427=m3
Thus, solving for m gives:
m=36427=43
Step 3
Find the ratio of height of shape A to height of shape C
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Answer
Finally, the ratio of the height of shape A to the height of shape C can be derived by using the ratios we found. We know: