Table height
A table has blocks of wood placed on and next to it. Can you work out how tall it is?
Age
14 to 16
Challenge level
Problem
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Four identical blocks of wood are placed touching a table in the positions shown.
How high is the table?
If you liked this problem, here is an NRICH task which challenges you to use similar mathematical ideas.
Student Solutions
Answer: 90 cm
Label the blocks
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$l$ and $w$ are on different sides of the equations so add to make them cancel: $$\begin{align}&\qquad 84+l=h+w\ \ \\
&\underline{+\quad 96+w=h+l\ \ }\\
&180 + l+w=2h+l+w\end{align}$$ so $2h=180$ and $h=90$