Question

If two supplementary angles differ by 78, then the larger angle is
a) 121 degree
b) 115 degree
c) 129 degree
d) 151 degree

Please help

Answer 1

Answer:

129° OPTION C.

Step-by-step explanation:

GIVEN:

TWO SUPPLEMENTARY ANGLES DIFFER BY 78.

TO FIND:

THE LARGER ANGLE

SOLUTION:

LET SMALL ANGLE BE X°

LARGER ANGLE BE Y°

AS THEY ARE SUPPLEMENTARY MEANS,

X+Y=180°

=>X=180-Y. ========> EQUATION 1.

NOW ATQ,

=>Y-X=78°

SUBTITUTING VALUE OF X FROM EQUATION 1;

=>Y-(180-Y)=78°

=>2Y-180°=78°

=>2Y=180°+78°=258°

=>Y=258°/2=129°.

HENCE MEASURE LARGER ANGLE IS 129°.