Situation $5$: A rectangular beam has the following properties: $b=300mm,d=450mm,$ and $d^{\text{'}}=65mm.$ Use $f_y=345$MPa and $f_c^{\text{'}}=34\mathrm{.}5$MPa. The beam is reinforced with $4-28mm$ diameter tension bars and $2,28mm$ diameter compression bars.

$25.$ Calculate the depth of compression block.

a$.151,103mm$

c$.176\mathrm{.}921mm$

b$.180,807mm$

d$.168\mathrm{.}724mm$

$26.$ Determine the reduction factor.

a$.0\mathrm{.}900$

c$.0\mathrm{.}650$

b$.0\mathrm{.}854$

d$.0\mathrm{.}877$

$27.$ Calculate the design moment strength $(kN-m)$ of the beam.

a$.470\mathrm{.}746$

c$.442,843$