Question 909698
I will plot height (h) on the horizontal axis and
I will plot weight (W) on the vertical axis
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You are given 2 points:
( 150, 70 ) and
( 165, 110 )
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(a)
You can use the general point-slope formula:
{{{ ( W - 70 ) / ( h - 150 ) = ( 110 - 70 ) / ( 165 - 150 ) }}}
{{{ ( W - 70 ) / ( h - 150 ) = 40 / 15 }}}
{{{ ( W - 70 ) / ( h - 150 ) = 8 / 3 }}}
Multiply both sides by {{{ ( h - 150 )*3 }}}
{{{ 3*( W - 70 ) = 8*( h - 150 ) }}}
{{{ 3W - 210 = 8h - 1200 }}}
{{{ 3W = 8h - 990 }}}
{{{ W = (8/3)*h - 330 }}}
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check the answer:
{{{ W = 70 }}}
{{{ 70 = (8/3)*h - 330 }}}
{{{ (8/3)*h = 400 }}}
{{{ 8h = 1200 }}}
{{{ h = 150 }}}
OK
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(b)
{{{ W = 90 }}}
{{{ 90 = (8/3)*h - 330 }}}
{{{ (8/3)*h = 420 }}}
{{{ 8h = 1260 }}}
{{{ h = 157.5 }}}
The student weighs 157.5 kg